You may want to check

master deed, HOA, public offering, etc.

For example, if the community allows 2 pets (excluding fish, bird) but he has 4, then you could report. If there is some appearance code, and the vegetable bed in any way doesn't comply, say too big, too high, too wide, doesn't look good, then report. Maybe he uses too much pesticide...

你主動找點能讓他惡心的，if you want.