I use femometer and that works great for me
Ovia fertility
I love Premom
I used Ovia and Glow for both before and after pregnancy
Fertility friend is a great free BBT tracker. I've used it along side other BBT trackers and find it most accurate. It doesn't look very pretty but it has a lot more you can log and customise
I have been using Flo for years & just the middle of last year started using the Premom app too. It is weird to get used to but I do enjoy the graphs & charts it keeps. I even have a thermometer that is bluetoothed to the app & I don’t have to plug in time & temp. It keeps a record for me ☺️ I am still using both apps because i’m used to logging my symptoms & period dates in Flo. But for all things TTC, it’s in my Premom app!