WowAce

Spyglass

Resizes some default UI frames (GuildUI, LootFrame, RaidInfo, TradeSkillUI and TrainerUI) to show more lines

Square Minimap and more

Database of Trainer locations for HandyNotes

Friends & Guild Data Broker plugin.

T_Tracking

Reno is a slash-command that can patch predefined options in a macro to change which abilities will be chosen.

A tool to appraise, estimate, or judge your equipment against the equipment of others.

Tells you the Tiller, what food they like, and if you have fed them today for the quests A Dish for ...

Tracks profession specific cooldowns and items across all your characters

A library to help with localization of talent trees.

Pet Theory

ShadowGreenLight helps you decide if recasting SWP/Corruption is worthwhile

Teleporters in Suramar? Sure, why not?

Tracks SendAddonMessage Spam

Timerbar embeddable library

LilSparky's Workshop mod for Trade Skills

Shows a circle on the minimap to indicate spell range

Display an informational fighter jet style HUD while flying or riding

Adds talent specialization role status to Grid.