Hi. I've been running a homebrew Pathfinder campaign for about five sessions now, and I want to give my players (a witch, a ranger/gunslinger, a paladin, and a magus) some kind of cool abilities that aren't necessarily the kind of thing they can take on their own.
For example, I've toyed with the idea of giving the witch the ability to turn her familiar into a giant toad with a breath weapon, or giving the ranger/gunslinger's animal companion the ability to rage.
I'm looking for ideas that are cool or interesting first, and possible with the rules second. I'm more than willing to bend the rules a little (or a lot) in order to let everyone have their fun, as long as it's not hilariously, painfully overpowered.
That really depends on what level they are.
Usually I steal and modify class features from other places
For example, the Paladin could use the samurais the Resolve class feature and the magus could gain the scrollmasters Scroll Blade (although modified to be not sucky). There are also a lot of obscure subsystems that you could use. For example, perhaps the Witch gets access to rituals (like Ritual Hex)?
I also like granting people SLAs. Maybe give the ranger access to the secrets of the named bullet spell under certain circumstances?
That really depends on what level they are.
They are 5th level, which is where they'll be staying for a while. And while I don't have a level cap for the campaign, I expect they'll max out at around 12th level or so.
There's a variety of ways you can do this depending on how much work you want to do.
The simplest method is give consumable magic items that mimic a high level spell as loot. You can make it a use-activated item that doesn't need a Use Magic Device check. For example, maybe the witch finds an elixir of polymorph familiar with CL 11 that that turns her familiar into a super toad.
If a player gets really attached to a particular effect, then maybe you can let the items be rechargeable and hand out "power crystals" or some other loot that recharges them.
The idea is letting the players be temporarily overpowered in a manner that you -- as a GM -- have control over and facilitate to create adventures that motivate the players and PCs.