Gravel/substrate vac. Here's how to easily start the suction.
Algae scraper. I use magnet for day-to-day and razor blade on a stick for more thorough cleaning. (Don't use a razor blade on acrylic.)
Buckets/lids. Nets. I also use a dolly to roll 5g pails through the house.
Turkey baster for sucking up waste, fry, etc.
Cheap pasta strainer (with handles that rest on the tank rims) to pour water into the tank to a) not disturb the substrate, and b) simulate rainy season when urging them to spawn.
Cheap towels.