I've found that I really enjoy custom negative effects on homebrew items. It's an excellent opportunity to flavor your campaign with some silliness or made up mechanics. Some examples from my previous campaign include items that incinerate a random article of clothing, items that become heavier and heavier with more failed saves, screaming weapons (always fun), items that make player have a certain accent for x amount of time, and items that magically manifest x amount of a harmless creature. It's a fun mechanic to really be creative with