I was on FB marketplace browsing for whatever good comes up in terms of lighting and apparently one seller posted the GU10 LED retrofit lamps in blue colour with 5mn style LED diodes in their original packaging. They were made by Alpha Innovations brand

This gave me a flashback to my childhood around 2006-2007 where on the shelves of B&Q, I saw these exact GU10 LED retrofit lamps (in two options of white and blue) from Alpha Innovations 0r a innovations. They were the only ones available as the rest of the shelves were CFLS and incandescents as well as fluorescent tubes etc

What was the first LED retrofit lamp you saw first in your life?

I have one of the type that you mention somewhere. It's absolutely terrible. Worse than even the worst CFLs color wise. It claims to be warm white, but it really isn't.
I use it at work, to demonstrate how far LED lighting has come in 20 years time. But i got that one well into the LED age.

Since i worked at a hardware store, i was there when all the incandescent showroom models were getting swapped out with LEDs. The decrease in heat at the lighting department was dramatic. This was around 2012-2014.
Before that, i didn't conciously see LEDs in interior lighting anywhere, because CFLs still shared the stage with incandescent.

The first generations of integrated LED lamps, no matter the brand, all had a decent number coming back on warranty claims. Philips was the dominant A-brand so i saw particularly many Philipses come back, also because they were quite expensive. People might not be as willing to drive back to the store to exchange the cheap 3 for 5 euro (or whatever it was) bottom shelf store brands lamps.

I think not a week went by without someone returning a broken Philips LED lamp. Though in the store itself, out of several hundred lamps i saw only one or two die during my limited time there.

At home, not a single LED lamp has failed so far, though i do think we also needed to warranty one in the early days of good quality LED lamps.

The first LED retrofits I saw were around the mid 1990s in the USA, and intended as replacements for tubular incandescent lamps that used to be popular in exit signs.  The incandescents usually had quite low light output, which was further reduced by red or green colour filters on the signs.  This made it relatively easy to replace them by red or green LEDs.  Typically the retrofit lamps comprised a string of series-connected 5mm LEDs, ballasted little more than a series capacitor.  They offered lower power consumption and much longer life than the filament lamps.  Typical brands of the time were Lumacell and Wattman, which were made in Canada and the USA.  I have a couple made in 1994 and 1996.

As far as I know the very first LED retrofit lamp was the Kodak darkroom safelight, made by MARL electronics in the UK.  That was a much larger E27/E26 based GLS-sized lamp with 20pcs 5mm LEDs all facing in the same direction, similar to the present snowcone type LED retrofits.  They were red 630nm LEDs and the 3W lamp was intended to replace 15W red-glass photographic darkroom lamps.

2005 I bought my first LED retrofit lamp from Focus DIY, (remember them)?, an 0.5 watt, 12 diode, GU10 made by Innovation for £10!
Absolutely ridiculous priced lamp for what use they were for household lighting! 
It was all new and state of the art to me at the time, but I realise now how much Focus were ripping people off for!, they probably bought them dirt cheap from China and slapped 800 % profit on them!
I still have it today.

Thanks for the stories. Yes I remember FOCUS DIY store (I was a very little child)

I didn't manage to get these GU10 LEDs on FB marketplace as someone snapped it up to my shock whilst I thought if I should drive all the way to Swindon, Wiltshire as that where the seller was based at

However I screenshotted that pic of the Gu10 LEDS

2008 +/- a year ordered a LED lamp from the back of popular mechanix was almost 200 dollars !! was about the same size as a 400 watt MH bulb with a extruded Aluminum housing and down facing LED array with a white cap
pulled 19 watts and was about as bright as a 13 watt CFL OR a 50 watt incandescent

The first retrofits I saw were led battens and sign board chips.

The led battens (no not led tubes, just battens) were slightly shorter than fluorescent tubes so could be put between the end connectors of fixtures and bypass them.

In signs where fluorescent tubes were used, small strings of led lights were used where each small board had three leds and each board was connected in parallel with long wires.

They weren't considered as separate lamps, manufacturers advertised them as retrofits.

The first retrofit I've ever seen was these fixtures that where converted from (incandescent, CFL and self ballasted MV) all to LEDs

Here is an other angle:

The first gotta be a 78mm R7s 150W halogen replacement, I think it was 15W instead, but in real life it was as dim as a fridge bulb, so much for "150W equivalent"... it fit in the socket but that was all, it was one of the early corn cob shaped ones with the exposed SMD diodes, it didn't last long because I replaced it with an actual 150W halogen after a while, it's for an outdoors floodlight so it can't be that dim, can't see a thing when it's pitch dark (it's a rural area so the road light is quite far away)
My mom bought it at a local hardware store and didn't return it afterwards so I must have it saved somewhere. I also have a similar bulb with an E27 thread that if I'm not mistaken it was meant for a similar style of floodlights that used CFLs instead of linear halogens or MH, I have attached an image so you know what I mean. It still works and it's also dim, draws about 20 watts but I'd say it's as bright as a 40 watt incandescent, so... not that bright for a room, this one uses 5050 style LEDs.

Around 2008/2009 I saw some those Lights of America PAR20/R20 retrofit lamps that used 5mm LEDs. I recall they were fairly expensive for their performance so I didn't buy one.

The oldest LED retrofit lamp I have are some tubular red LED B15 based lamps from 1994. They were used to replace incandescent lamps in exit signs.

IIRC traffic signal LED retrofit modules came out in the 90s too. I think reds were the first, and the hand/man retrofits the last to come out. The early hand/man retrofits used orange LEDs for the hand and halogen driven fibre optics for the man instead of the expensive white LEDs. 

The first retrofit I had ever seen was a small child at Costco, wayyy back when those first smushed cyclindrical LED abominations started to hit the market. I remember the blister pack in which it came, as well as its associated "ConservEnergy" moniker. Probably a close second was the Philips S-Line winner (our favorite remote-phosphored beast). Though this was at a friend's place in sometime 2013. Reason why I remember it so vividly was because they used this gawdy looking thing in an enclosed garage / exterior wall-mount fixture. I just remember pointing and staring, my mouth agape. Though our first true use of LED (more than one or two lamps) was probably late 2013 with Feit's slightly lighter and less abominably clunky LED offering, which came in what I believe was a six pack.

Then I remember breaking the shade on my room's fan by accident, and my parents putting up a new one in its place. I believe the lamps used there were early Philips "WarmTone" LEDs with that weird extrusion in the center. Though hilariously enough I remember them to be as compact as modern-day Snowcones (this was around 2014, so I doubt they were full snowcones). I know they were LED for certain though.

Though, on a small side note, I remember my dad installing two induction vanity lights of some obscure European manufacture. They were a bright daylight white, extremely thin and long fittings. Or maybe they were CCFL... not certain. Anyways, I digress.

Attached below is the best photo I could find (from the house listing) of these luminaires. Just a reflection unfortunately, unless there are other photos on a hard drive somewhere....

I remember my dad bought some leds for the gu10 bathroom spots. Halogen bulbs were exploding if water hit them and cfls were dim at startup. 15 years later they still work.

I begun to see led lamp in GU10 form (Osram) in early 2010's.
Then i bought my first led lamp in 2011-2012 (i don't have it anymore, and i don't remember the exact year).

As far as I know the very first LED retrofit lamp was the Kodak darkroom safelight

To deviate from the topic: I guess darkroom lighting was altogether the first application where LEDs were used not only as indicators? In the GDR some handiwork suggestions for that have been published in the eighties.

The first retrofit I'm aware of was for gas light: On mechanical railway signals, with attached propane bottle. It not only required a circulation of the bottles for refill, also frequent evening/night strolls of the signalmen when a mantle broke. Thus an electrical solution has been developed around 25 years ago: Solar cells, charging a battery, and LED panels. These panels were still a mixture of mostly yellow plus some red and green, the blue LED was no real-world product yet.

If the question is meant in the narrow sense of general lighting applications, then it were also in my case GU10 retrofits. I spotted the first ones at a time when E27 and E14 was still undisputed CFL territory and I would not have guessed how quickly this technology would disappear.

Amongst these GU10 retrofits were the ones in a restaurant that are still there, not showing any signs of weakness after, if I remember correct, more than ten years.