Add-ons built in the middle of real projects, then polished until they disappear into the workflow. Every listing shows exactly what you get before you get it.

Every listing shows what it does, what it needs, and what changed in the latest version, before you spend anything.
Every add-on links to its Gumroad and Superhive pages. Pick the store you already use.
Buy once and keep getting new versions. The version history on each page shows what changed.
Each listing states the oldest Blender it supports, so nothing surprises you after checkout.