Most of the guides and discussions that are easier to find for animal companion builds are either older and don't incorporate Ultimate Wilderness options, or they're focused more around damage output. My hope here is to get some discussion going for more ideas.
The idea is more along the lines of utility options and tactics for a companion rather than outright damage from the companion. Things like battlefield control/disruption, buffs or debuffs.
-Menacing enchantment on an Amulet of Mighty Fists: provides an additional +2 bonus to allies if a creature is flanked
-Disruptive Companion feat: A mini version of the Disruptive feat, plus makes it harder to Take 10, even with abilities that allow for it.
-Broken Wing/Wounded Paw Gambit teamwork feats: Creates attacks of opportunity
-Skirmisher tricks: For hunters or skirmisher rangers. A lot of options here.
-Vine Strike spell: Not PFS legal, but otherwise an option. Potential for the entangled condition.
While there are Combat Maneuver options, I'm looking outside of them as I've found they tend to lose steam for a companion after the early levels. The lower BAB progression doesn't seem keep up well with the increased HD/BAB and Strength progression of creatures.
I put menacing on most of my ACs. Even better when used with outflank.
Hunter's and sacred huntmaster's excel at teamwork feats. Tandem trip works well. Camel's can work with ranged teamwork feats for pure hilarity.
Manuvers work up to level 16, the highest I have used them on an AC. The trick is to dispel freedoms of movement then grapple easy targets like the wizard or cleric (non-melee).
They can aid casters buy intimidating. There are animal companion specific feats to help this or take intimidating prowess. -2 to saves is a decent enough rebuff when it is bonus.
Bodyguard and in harm's way are great ways to make an AC useful at every level.
Means of flight. My mounted inquisitor on a flying mount is a monster.
For full round casting times + a mount means still being able to move. Great for 1-round like metamagic modified spells.
Don't ignore scent/other senses, which arw a life saver for knowing where to toss glitterdust or farie fire.
Here is my druids support animal companion.
Deinotherium trample get you into flanking easily, sweep knocks prone without a cmb check then I have the body guard feat tree. Finally extra traits for sacred touch.
Yep flanking buddy, tripper, stabilizer, ac booster and damage soaker.
For a little more context for my specific use-case, I'm looking for things to do with a dog companion of a ranged hunter. The teamwork feats the hunter will be provide are pretty much taken care of, so I'm not too worried there. I'm looking for more for the dog to do than just stand there and provide flanking bonuses to other party members and Coordinated Shot benefits.
I have a melee hunter built around a big cat mount with all the bells and whistles for creating AoO's through Pack Flanking, Paired Opportunist, and Broken Wing Gambit. Looking to try the other path.
Utility usually means things other than attack/buff/debuff/BFC - information gathering or out of combat stuff like scouting or getting over obstacles mostly. A flying companion has uses in that respect and a courtly hunters can too. Companions with odd senses like scent or blindsense might qualify as such. I once had a roc animal companion with the scrutinize spell feat and a couple of traits (additional traits feat) to make it work.
The animal companion of a spellcaster with polymorph spells (or a few others like the mount of a cavalier of the [ACG] Order of the Beast) can be made to shapeshift via share spells or otherwise. Sharing a dazing burning gaze can be useful for controlling enemy minions and shared multi-touch attack spells can work on harder targets.
Ultimate Wilderness includes some feats which let flyers knock others around. I haven't seen them in use but they should work for a little BFC.
Getting your animal companion to deliberately fail its save can be a useful way of delivering silence or darkness, or blocking off a passage with resilient sphere.
A ranged hunter with a dog companion? That suggests it won't get to large+ size (which means you're right, combat maneuvers will fade in usefulness later on) and the hunter won't usually have time to spare to buff it much. Which means in turn you're mostly looking at the feats of the animal companion, plus perhaps the odd magic item.
There's nothing stopping an animal companion getting ranks in the use magic device skill if it has Int 3+. Item mastery feats have prereqs based on the users base fort save and (lowish) ranks in UMD. You can do something... unexpected there if you like. With curative mastery if nothing else.