This shoe was already rad before they went with the gum sole, now it’s hella rad
I have no doubt that the idea of using LEGO minifigures for tabletop miniatures occurred independently dozens of different times in many different groups; it would have been tempting as far back as the first release of castle-themed LEGO in 1978 (only four years after D&D was released).
For me, the pieces (get it) didn’t fall together until 2008, when LEGO’s castle theme first introduced orc minifigures (LEGO calls them “trolls”, or at least they did back then, before they were producing LOTR licensed sets). Since my only D&D character at that time was a half-orc, making a decent LEGO mini was impossible for me until the orc heads were available.
The other important step in making miniatures possible for most of the base races was the creation of short legs; those came out earlier, around 2002 (I first saw them used for Yoda and young Boba Fett). These legs are pretty necessary if you want a gnome, halfling, or dwarf.
Once those two things were available, the options exploded; there was already a great variety of medieval armor, weapons, and clothing available to choose from. Hair and face options for female PCs have become more readily available as time has gone on (when I was first making LEGO minis for D&D in 2008, I only had one female hairpiece; I probably have upwards of ten now).
The first party of PCs I ever made. Back row, left to right: wizard, ranger, halfling bard, druid. First Row: fighter/rogue, half-orc paladin, animal companion (leopard)
Here we have a paladin and monk created by my players in a much more recent campaign.
Sometimes LEGO minifigures can mix nicely with official “miniatures”.
That’s an aspect of Ehlonna, so… it may be wise to run in the other direction.
A Blackguard in service to Nerull approaches, his posse in tow.
Skeletons are pretty useful, too.
You’d be surprised what you can make with the right pieces.
For the most part I still use regular miniatures for monsters, though if the enemies are human or undead I can often make LEGO minis for them. Even beyond that, options for making LEGO monsters have expanded greatly over the past few years. Here are just a few examples:
Lizard folk: http://lego.wikia.com/wiki/Lizard_Man
A practical solution for every gaming group? Nah. Super cool? Yeah.