RCS is planned for the future, but awaiting more public API support.
Looks like Uptodown and Amazon are worth trying.
This is supposed to let you use Keepass2Android with an NFC Yubikey to unlock it.
Requires Android 4.0 ics or higher
Crostini, Crouton, and ARC Welder (Linux and Android environments)
a handy front-end for Flickr photos
A server platform that lets you self-host multiple applications, intended to maximize freedom and privacy. Based mostly around Nextcloud, but the mobile app seems to do more, like Ethercalc.
It's a full OS, so you'd have to figure out how to get it installed on a VM through a hosting provider, or run it at home/work. Unless maybe it can be installed on top of plain Debian?
Doesn't seem to save an archived copy by default like Shiori, and more Android app options
