Reddit mentions of Xcelite 378M Thin Profile Long Reach Electronic Plier, Serrated Jaw, 5-1/2" Length, 1-1/4" Jaw Length

These might be some more "advanced items" but I have found them all to be of extreme usefulness and not too expensive to justify. Note: Where provided Amazon links are for reference only and I have no financial interest in the sale of the item listed.

- A set of ball-tipped metric hex key wrenches. The ball end allows you to get around obstacles and still rotate the fastener. https://www.amazon.com/Bondhus-10946-Balldriver-L-wrenches-1-5-5mm/dp/B0006O4AEC Note: You'll only need, IIRC, three sizes but the set is still cheaper than buying the individual keys.

- A clean popsicle stick works great to "scrape" or swipe the occasional pre-print and post-print drip from a hot nozzle's orifice and cannot damage the metal. Actually a suggested tool by a lot of industrial hot melt adhesive system companies for the reasons I just stated.

- A small open topped container, about the size of a kids sand pail, for all the waste support, brim, raft and skirt material you'll be generating. I happened to have a clean empty plastic 1 gallon OJ jug and cut off the top where the jug started to narrow leaving me a 8" tall "bucket". Small enough to keep next to the machine because tiny bits of PLA...

- A small magnifying glass, good for layer quality inspections.

- A small AA powered penlight, I had one anyway on hand anyway but was surprised at how often I needed it around the printer that it now lives there full time.

- A plastic paint scraper since I do lots of technical prints that leave large amounts of random first layer support spaghetti stuck all over the build plate. https://www.amazon.com/Red-Devil-4718-3-Piece-Plastic/dp/B001SBJIA8 (I know for a fact this set I've linked to is soft enough not to scratch the PEI coating. You actually only want the smallest scraper in the set, the other two can be used for what ever but at $2.99 per set even if you never need the larger ones it's no big loss.)

- A small table-top digital humidity and temperature gauge to monitor your printer's local "micro-climate". At the beginning I found that there was some temp/humidity related print quality issues where I had first set up my printer that forced me to relocate it and the only way I figured that out was by using this gauge. https://www.amazon.com/gp/product/B0013BKDO8/

- Good quality needle nose pliers with some grip to them. The pliers Prusa included with the printer are, IMNSHO, junk. I have both of these and am satisfied with both:

Good: https://www.amazon.com/Xcelite-378M-Profile-Electronic-Serrated/dp/B004UNFK58

Better (and cheaper): https://www.amazon.com/gp/product/B00FZPHEW2/

I use these electronics pliers and they work great.

You can also get straight snap ring pliers. Don't get the universal ones with multiple heads, the head just turns when you try to turn the pill.