The AutoTurnIn addon can handle accepting and turning in completed quests and choosing rewards. It can decide which reward to select by specifying options and if no suitable item is offered, the highest value one may be looted. Afterwards, it can also equip the chosen reward. Complete automated quest acceptance and completion. May handle just daily quests or any others you find in your adventures.

Auto (or by button) junk selling, map coordinates for player / mouse point, quest levels on so on.

Please, take a look at the SimplestAntispam mod. It greatly helps to clean out the chats in the cities and populated zones

Quests

Any quest (regular, daily). Trivial (grey ones) may be configured to skip.
Daily.
Any except daily.
Only turn in quests, but not accept new
Ignore particular NPC on your decision

Some quests have to be skipped for their bugged nature. Sometime quest may be "available" but addon will will ignore it - check if you have enough required currency to accept or complete it.

Rewards

Before completion quest requirements must be satisfied, i.e. it's visible state must be presented as a bright yellow question mark (all rabbits are killed, gems collected or what else the quest-giver wants). Some quests requires a special items to be transfered to quest giver. For example, Calling the Ancients requires addon to know this particular quest, if it does then addon may check if you actually have required items and turn quest in or ignore it until you collect the missing amount.

Reward may be chosen based on desired stats or type, it's cost for future selling or addon may stop at all if any rewards but money exist. Also addon can't make a clever decision on trinkets so you'll have to choose by your own.

Additional functionality

If you need to interact with an NPC without accepting or completing quests, the "toggle key" allows you to. Press it and click on NPC and all quest will be ignored. The key works only for one interaction and if you want to completely turn addon off you have to check the corresponding check-box.
If you want to read quest final text check the "show reward text" option. The story will appear in a chat window.
Command line uses /au to open configuration window. Also addon may be registered on titan panel, chocolate bar and similar addons.
For Darkmoon Faire you can configure teleport to the island, teleport from the coast to cannon, autogame starting.
Silver tournament (WotLK) may be automated in part of rewarding so you can set to loot writ or recommendation.

Credits

Code changes: Katyl, Nikolas-x, Alvana, uickBASIC, theondry, Yevgeniy (Gene) Nazarov, ievil, TradOrtiz, fpiceail, redpancho, ChrisKader, Skadabucci,
Localization: French : whitelightelgringo. German: AlexL1986. Italian: Eniac73
Supporters: Kermit, PlsLater, H.Kendall, B. Birch. P.Jermakian

Videos, sadly - mostly outdated (all credits to ther authors):

English Youtube video
German Youtube guide
Russian Youtube video