Jacona

Well damn this thing is still alive.

Well if you do end up getting something then the Fulla 2 is a pretty great entry level Amp/Dac, especially if you choose to get some active speakers later on.

VE Monks 95% of the time

What kind of games do you usually play? What type of grip style do you find yourself using/is the most comfortable?

Custom One Pros might be a good match, though they are a bit more expensive at 150ish There's also the Shure 440/840 in which some people prefer over the ATH-MX0 line

What type of music do you usually listen to?

SteelSeries Rival 100? Not the best sensor but should get the job done. There was a mouse on massdrop a while ago that used the Sensei mouse shape with a 3360 sensor all for about $40, but it's over now.

Dirt is often embedded into the mousepad and would require a sponge or a brush to properly clean it (even if the pad looks clean from a wiping). Patchy dirt areas also have caused some tracking issues for me.

IDK if I can find any keyboard that can fulfill all the requirements, but linear switches with o-rings or landing pads are usually (one of) the most quiet when it comes to Cherry type switches. Corsair has the Cherry MX silent switches but not sure if it's available in a TKL format. There are a few Magicforce keyboards that are a 65% layout with a aluminum back-plate and can go for as low as 40 USD. If you want to prioritize silent, then there are Matias silent keyboards that are noticeably quieter than cherry switches. Ducky Shine mini V60 with matias switches

Was the pad still wet when you tried it? I've had tracking problems with my Naos 7000 when I tried it after washing my pad. If so, just let it dry and try again later. Cleaning the sensor area of dust and/or particles can help too.

Well the 3366 (G303) have higher tracking speed then the AM010 (G402), so if you use low sensitivity then the G303 would be best. If you use higher sensitivity then the G402 should be fine.

I thought you said T50RP at first but then saw there was an extra H and 0. Well the 400i definitely measures better than those TH500RP. Fostex basically took the T50RP drivers and put them in an open TH-900 housing. The 400i are 93dB/(mw?), so it's kinda is hard to drive but could probably get away if your motherboard is pretty decent like a Z or X board. Try it and if it's not loud enough there's the Magni 2 B-stock for like $90.

How about some Mionix mouse? The Naos 7000 uses the 3310 and has an aggressive ergonomic shape. The Castor also uses the 3310 but is a bit more subtle with it's shape. Both have been stated to be very comfortable.

Aftermarket RX 480 might be your best bet, unless you can somehow find a GTX 970 under ~240.

The scroll wheel and the material used on the side are different between the original Rival and the Rival 300. The original Rival had some durability problem with the material they used, so it'll be best to get the updated 300 version.