ATTENTION PLASMA WIDGET, THEME AND ADD-ON DEVELOPERS:
KDE loves all your stuff, but you need to port it for it to work in #Plasma6. We have created a handy, easy-to-follow guide for extensions and widgets at
https://develop.kde.org/docs/plasma/widget/porting_kf6/
Theme developers, please check out this:
https://develop.kde.org/docs/plasma/theme/theme-porting-to-plasma6/
Porting is quite straightforward and should not take you long.
Keep your users happy! Port your stuff!
You can find a lot of tiling extensions in the store. Although I don’t know how many of them were ported to KDE 6 already. I haven’t used others, since most of them are designed for a tiling-first workflow. I want mostly floating windows with just selective tiling when I need it.