Spoilers may be present.
So, I've seen a lot of speculation as to who, or "what" K.O.'s dad is. A few people are saying Lazerblast, some say "just a stranger/someone we haven't seen yet", and, sometimes Lord Boxman (which, honestly makes no sense)
Now, I have seen this a few times, and, I think this makes the most sense: Mr. Gar is K.O.'s dad
Evidence? Well, it's practically staring you in the face in "Glory Days", or, in, "We Messed Up". Gar has a ton of pictures and articles from his former residence, P.O.I.N.T., most of them being of, guess who? Silver Spark / Carol / K.O.'s mom.
In "Face Your Fears", it is thought that Gar was afraid of Lazerblast, but, was actually CAROL! They could've gotten together and accidently (or not) had K.O., but something happened, aka the "Sandwhich incident", and they broke up. Now, onto another part, that could also make a bit of sense.
Lazerblast could also be.
This'll be edited and more will be added when more non-filler episodes come out. Thanks for reading!