In terms of dagger sources, Jay Vail wrote a book that gives a good overview. For a primary source I started with the Codex Wallerstein because it's commercially available & I do a lot of work from there, both in terms of dagger work & Ringen.
For kicks, I’ve seen knees to the groin/body, push kicks, stomping kicks to the knee/shin/foot & a snap kick to the groin. No high kicks or round kicks that I’ve seen.
Like I said, it’s my impression that punches & other hand blows were used to close the distance in order to grapple & that they were more often empty handed versions of dagger strikes then an independently developed system of unarmed striking. So to start try a straight right cross, a hammer fist blow with the right hand & a hooking palm strike with the right hand. Try them both by turning the hip like a boxer & by stepping through as if you were cutting with a Longsword. I wouldn’t consider that a comprehensive list of period strikes or by any means a complete system of unarmed striking, but it’s a good place to start in getting a feel for how strikes were thrown in kampfringen.