I’ve recently been experimenting with a bit of a makeshift “mini-Chinese” style opening on 13x13.
Start with the top right 4-4, then a 3-4 stone facing white’s stone, then a low approach to White’s bottom left corner. (See Review: https://online-go.com/demo/205513)
I like it since the third move serves as both an approach and a pincer if your opponent ever tries to come near your 3-4 stone. If you manage to enclose the 3-4 corner, it gives you great influence and sizable territory.
Another option is “The Orthodox”, especially against duel 4-4 openings. The corner enclosure gives you a significant territory advantage that’s hard for white to overcome - especially since black can always do 3-3 corner invasions.
I may easily be overlooking some flaws with these openings… but it seems to work at a kyu level. It’s gotten me to #32 and counting on the site 13x13 ladder so far.