Addons for pet battles
There are quite a lot of helpful addons for pet battlers. I want to list some especially useful ones here, sorted by priority:
For me this is the most important addon for pet battlers! It replaces our pet journal with a much more advanced version.
It provides the option to save your teams and assign them to specific opponents so they are automatically selected whenever you face them. These teams can be arranged in tabs and you can attach notes and scripts to them. Furthermore one or more slots in your teams can be filled with leveling pets (pets you want to level up next) which are drawn from a list you can create yourself. You can even adapt those leveling slots to meet certain conditions of any encounter. All of this happens automatically.
This addon also offers some neat options to filter and search for pets.
Link to the addon: https://www.curseforge.com/wow/addons/rematch
2. Battle Pet Breed ID
Pets can have different "breeds" which determine how their stats are being distributed with every level they gain. These differences can be crucial to the succsess or failure of a pet in some situations. Unfortunately the base game doesn't show the breeds of the pets. That's where the addon Battle Pet Breed ID comes into play: it shows which breed a certain pet has and it also lists all the possible alternative breeds that every single pet can come in.
Link to the addon: https://www.curseforge.com/wow/addons/battle_pet_breedid
3. Derangement's Pet Battle Cooldowns
The addon displays all (selected) abilities, cooldowns, buffs and debuffs including their remaining duration of every pet in a match. Especially in PvP this is essential.
Link to the addon: https://www.curseforge.com/wow/addons/derangement-pet-battle-cooldowns
PetTracker has many nice features that may prove handy for pet battlers. It is particularly helpful for completing the own collection. It shows the spawning locations (including vendors and such) of pets on your map. It also offers some other services like having its own breed display with special icons or showing the selected abilities of your opponent. However there are way better alternative addons for these jobs and that's why I recommend to use PetTracker only as a tool for collecting pets.
Link to the addon: https://www.curseforge.com/wow/addons/pettracker
5. Battle Pet Battle Stats
Another small addon that displays the stats of pets in a match with more detail (e.g. showing percentages of hitpoints for certain thresholds). It additionally gives you a more apparent presentation of the current match-round.
Link to the addon: https://www.curseforge.com/wow/addons/battle-pet-battle-stats
6. Battle Pet Daily Tamer
This addon shows you tamers and quests (including world quests) on your map.
Link to the addon: https://www.curseforge.com/wow/addons/battle-pet-daily-tamer
7. tdBattlePetScript (Rematch)
This addon or rather these addons are most likely attractive only to the more experienced (or lazy) players.
The addon Rematch in conjunction with the above-named addons can make pet battles a lot easier.
If correctly setup you can play an entire match pressing just one single button.
Here is a guide on how to install and use these addons: https://wow-petguide.com/index.php?m=UsingTDScripts
And you can also find a guide for writing scripts on your own here https://wow-petguide.com/index.php?m=TDScripts
This too is meant to simplify repeatable fights and therefor is a nice addition to TD-Scripts.
UltraSquirt uses the one-button function of TD-Scripts for the fights and carries that over outside of them to heal your pets and restart a fight.
The addon works for Squirt as well as for the repeatable trainer encounters from legion.
Once you've installed the addon you have to type "/ultra" to activate or deactivate it. Use the target selection to set it up for the trainer you want to use it on.
The options are very simple but you can still read them up in the addon's description on CurseForge.
Pressing the space button (default setting) will heal your pets (either the spell or with bandages, alternatively via the NPC at Squirt), navigate through a fight using TD-Script and reengage with the trainer.
Link to the addon: https://www.curseforge.com/wow/addons/ultrasquirt