If possible, F-Droid could/should be used as your first stop for looking for a particular app or type of app. Obviously you won't find Tumblr on there, but it's got you covered for replacement apps for things like SMS messages, a photo gallery, a calculator, flashlight, notepad, file editor... You get the idea.
Simplest path is probably to use the old simple mobile tools recorder app on fdroid, which won't be getting any updates. Fossify will likely release their recorder app very shortly, which will essentially be the next update for the smt recorder app.
It is already under active development, they just haven't gotten the first release yet.
Edit:
Another interesting one is DroidRec. It is usually used and seen as a screen recorder, but it has three simple toggles for screen video, device audio, and microphone. If you turn off screen and device audio, it becomes a very nice voice recorder.
Is it part of the apps that have been recently sold to a commercial company? If so, you have to uninstall it and download the "Fossify" equivalent to keep the open source version.
Finally! Now I can finally have a voice recorder spy on me!
That's what I was missing back in the 90s, playing with a portable tape recorder without any strangers eavesdropping on everything I said. Isn't tevhnology grand!
(stock Android) I've yet to find any android call recording app that works on a device that doesn't have permission from Google to use the built in call recording features :/
~9mo ago they all got broken by an android update and haven't worked since.