My dog eats the same foods I do, so human food isn't a 'treat', it's her dinner. But for human junk food as an occasional treat, she gets hot dogs, bits of pizza, popcorn, chips, fries, or whatever other junk food I happen to be eating when she's around (if it's okay for her of course). I almost always get her a hot dog if she's in the car with me and I stop at 7-11, but sometimes they're out so I get her a beef or pork steamed bun instead and only give her half then and half later since they're so big.
Mine get a good range...
Pretty much anything safe for them they will get from time to time either in stuffed kongs or sharing my food (rewards for polite behavior like sitting or in a down beside me, settled on a bed/mat, etc. while I eat.)
Formal training sessions and classes...
I use a variety. Chicken, beef, cheese sticks, meat balls/diced meat loaf... often scraps or leftovers.
Not people food but I also use a lot of ''complete dog foods'' because I can grab and go. And just use a serving for a meal instead of figuring out how to reduce or adjust their regular dog food accordingly. I like Fresh Pet (variety that looks like meatballs - downside is needs refrigerated) a lot and recently have been using vital Essential mini nibs (freeze dried raw in kibble sized pieces) as I needed a very pocket friendly option I can have out all day.
My Shiba won't eat any human food that's not meat or cheese so he doesn't really get a lot of human food as treats. He used to like bananas, blueberries but now he just plays with the blueberries, smushes them with his tongue and leaves it on the floor for me to step on. Grrr...
My pittie puppy on the other hand will eat anything. She LOVES LOVES LOOOOVES baby carrots so I use that for training. I'll make her wait while I go hide it somewhere and when I say "go find it!" she dashes off and sniffs for it. I guess because she's only 4 months, she'll treat anything type of food as a treat lol
My dog would eat anything offered, though, thankfully, he has a solid "leave it," so if it's something he shouldn't take, he won't if told not to do that. He'll happily eat almost any vegetable or fruit and is particularly fond of cherry tomatoes. Lately, he's developed a taste for Clementines, which I was sure he wouldn't eat.
And though I normally can eat in front with him right beside me on the couch and not have to worry about anything other than the occasional longing glance, the other night, out of absolutely nowhere, he suddenly shoved his entire head in the bag of popcorn that was in my lap. When I told him "No! Leave it!", he yanked his head out of the bed, looked at me as if he just didn't know what had come over him, and left the room. Hasn't done anything like that before or since, so I don't know what he was thinking either.
I treat my dog to peanut butter, carrots, sausages the odd time and maybe a small bit of cheese. Or left over rice, pasta, veg (depending on what type). I try not to give too many tit bits because i despise dogs that sit staring at you waiting for scraps when your eating. But now and again is fine and one of my dogs has a great "leave it" - other one has a LOT to learn haha
Betsy would eat literally anything!! but she has a sensitive tummy, so I have to be careful (I have paid the price in the past when I've given her the wrong thing!!) She does like to share my toast, little bits of ham is definitely a favourite. My last dog loved carrot sticks, I tried to introduce them to Betsy, but I just ended up finding them around the house where she'd given up on them
One thing she doesn't do though is sit & watch us at the table, despite being a piglet in general, she used to, but doesn't bother now.