One of the best things about non-formal kimono is how flexible it is. You can technically speaking pair it with almost whatever as long as you know the general rules of wearing kimono and the look you're aiming for, and just have fun with it. Of course TPO matters a lot (Time, Place, Occasion) but when it's Morning + Home + Lazing About there's almost no limits.
One of my personal favourites is a shirt under kimono. It's very indoors friendly, won't get too hot (it was way too cold for outdoors though XD), comfortable and easy and there's no worry about sweating since the shirt can be just thrown in the wash. I like to wear Western shoes with kimono too, although sometimes I'm doing it simply because it's so cold outside so don't take that as a 100% fashion statement. They do match the shirt in style though...
Another obi, a completely different look. Accessorizing makes all the difference. Just the way the obi is tied can be the defining thing (these obis are both selfmade hanhabas and as such they're on the low rungs of the formality ladder).
Here's a better look at the front. It's a really long and soft obi so I turned it around in the back to create that fun zigzag effect.
Nothing special going on in the back, just a simple anesan musubi.
Front after running around for a bit. I was happy to see how well the shape held, although I'd like to see if I could avoid the side wrinkles with an extra layer of stiffener underneath.
This musubi... I have no idea what it is, even. I was thinking of going for a simple kaino kuchi but then I began to play with it instead and ended up folding it into this shape. The te end goes through that "pocket" part and is then stuffed into the obi. I can't say how well it would hold since I only wore it for about half an hour, but I would say it felt very similar to a kaino kuchi - meaning accidents are possible. XD
Front. Same thing about the extra layer of stiffener here. As you can see in both detail shots I'm wearing an obi ita but it's not enough to keep the obi from wrinkling when I move about.