.... and a test kit (liquid one ... people like the API master kit) to monitor your levels,
a good thermometer to take the water temperature (heater dials are inaccurate so you need to double check the temp.)
Also don't forget a clean (new) bucket for your water changes, and a good dechlorinator (I like Prime) for the water .... and lots of old towels for messes! <I always spill water working on the tanks.>
Some fish also like to have some drift wood to chew on (eg Plecos), others like some hiding places - plants (real or fake), decorations, caves ...
80 gal FW with 30 gal DIY wet/dry/sump.
9 fancy golds, 1 hillstream loaches, 1 rubber-lip pleco (C. thomasi), 3 SAEs, small school of white cloud minnows, planted.