I have no affiliation with any of the links, other than I’ve used them myself with good results.
The Minis
Elder Brain
The elder brain I used to end a year long campaign and try to TPK my players. When they started to win I escalated the fight to this Elder Brain Dragon which is probably not meant for FDM printing but did OK.
Mind Flayers
You can’t have an Elder Brain without some Mind Flayers for it to command. I used two models for these.
Kenku Cleric
I usually purchase an official WizKids mini for each of my players because they look cool and have a lot more detail than most of the free STLs I find.
However, this player wanted to create a Kenku Life Domain Cleric and this Death Cleric model was as close as I could find. I modified the file to remove the skull from the shield and changed the flail to a mace by removing the chain.
Pit Fiend
I haven’t had a chance to drop this one on the table yet, but it’s coming
Misc. Prints
Dice Tower
We mostly use the DnD Beyond app to roll but I make the players use this tower with a solid black d20 for death saves.
Other Resources
Bambu Lab A1 Mini
This is the printer I use. It’s done great so far.
I haven’t added the AMS Lite for multi-color yet since I primarily print and paint minis, but it’s calling my name.
Printing Advice
I’m still new to 3D printing but these resources have helped me a lot so far.
Tomb of 3D Printed Horrors (Fat Dragon Games)
Great video series on FDM minis and 3D printing in general.
BamBam Print
Good tutorials on the Bambu slicer software.