Thanks for your interest!

What Prusa does your friend own? If it is an earlier model then it might just be that it's not up to scratch printing such high detail. Also are there any specific issues, such as prints failing/jamming, detail not coming through, supports failing?

The smallest resolution you can reliably print is 0.5mm so a good test might be to print the model at the same resolution but at twice the size. This will help you to identify if there are any issues with areas that were too small/thin on the original scale. 
There are also a few different kinds of support structures you can print with, standard pillars, hexagons etc.

If the models come with a base then it is definitely better to print them with the base on the print bed, but if it's just the character then you can also try orienting it on different angles to get the least amount of overhang.

Thanks!

The purple worm is famous across DnD campaigns but so is the generic giant death worm, not constrained by colour or creed!

Wow!

Prints like a dream and without supports!

If you already answered this question, my apologies. But you have made it seem clear that larger models are easier to print. I purchased several smaller figures 3' scale size Kobolds.from heroforge. Digital stl files. Was this a mistake? Can I not expect to print them well? Or is there a really good 3d printer that can handle smaller prints? Thank you for your advice!

Larger prints are always going to be easier to print well just because they're less delicate but I'm always surprised how much detail I get out of my printer. 
FDM printers which use spools of filament are slowly going out of style as people move to SLA printers which use a bed of resin and lasers to cure each layer, but they are still more expensive.
If you already have the models and the 3D printer then give those models a try. Ultimately I would say an SLA printer like the Anycubic Photon or Prusa SL1 are great investments if you really want to get into printing miniatures but obviously there is the cost. I still only use the Prusa mk3 which is FDM and I think i get a good amount of detail out of it. One day I will get an SLA printer but what turns me off right now is the Price and the hassle of dealing with the resin material.

FDM

Pros:
Cheaper 
Cheaper/universal material (filament)
Less printer setup time

Cons:
Finest detail 0.05mm layer height
Possibility of jams

SLA

Pros:
Finest detail 0.01mm layer height
Great detail
Easier support removal

Cons:
Expensive
Expensive Resin
Resin isn't usually safe to touch while uncured
Usually need post UV curing in another container

I love how alive your 3D prints look! I'm sure the size helps avoiding ''low quality'' renders, but still, it's super impressive and motivating!

Mimic dice box, don't lose a finger!

3D printed mimic dicebox. The teeth are as sharp as they look!

When are you going to have an Etsy store? Lol. Want your Slaads, this dice box, etc...

I'm glad you like them so much,

I'm slowly putting them up on my CGtrader: https://www.cgtrader.com/dca-tabletop

So far the Slaad models are up there!

I saw that with your link earlier, but our 3D printers are not very good. Our school is looking into other models. Pretty certain next school year we will purchase a better machine. I look forward to ordering then!

I would love to see that mimic dice box painted up and full of shiny dice!! I love it!

Ok...if you can humor me. If I wanted to print your models and others at the best print quality which printer would you get? Our school cannot afford the "Formlabs Form2 SLA" at $2500...but what would you suggest for $1000? That is reasonable for our school. My colleague is teaching Laser printing technology with an Epilog Laser and there is a good chance we will be exploring printing minis and painting them as an Art/Technology class. (Super lucky.) So, if you had $1000 to spend on a printer that would do well printing creations on Thingiverse what would you want? Opinions are very welcome. Thank you!   

I'd go with the Anycubic Photon printer http://www.anycubic3d.com/products/show/1359.html

It actually comes in around $500 USD so will give you lots of spare money to buy resin without going overboard. Definitely one of the best budget resin printers you can buy so guaranteed to get the best detail from your prints.

Trying out my own character designs, feeling very aquatic at the moment.

When we buy these, are they just the design or do you ship a physical mini. I have no access to a 35 printer so I’d love if you started selling the physical minis. They look amazing!

Thanks!

Currently any files for sale are through CG Trader and are so just the files. If I ever get to selling the physical mini's myself I think I'd have to upgrade my own printer setup to take the extra work. But don't worry if I do I'll be letting everyone know.

Campaign creatures don't always have to be enemies to fight. Sometimes they can be friendly little characters minding their own business...

I love them both so much! You are very talented!