Periodic Calendar VS Clue

Well there is but I don't know if I'd trust it, frankly. Periodic Calendar. Open source and licensed under the GPLv3. Thing is I don't think it's maintained anymore; the most recent version was released 7 years ago, and the most recent copyright date I've found was from 2013. Source: almost 2 years ago

For a period tracking app, you can use Clue. They also has many well researched articles on the female reproductive system on their app and their website Hello Clue. Source: about 1 year ago

Here's the website, they have an Apple version too: https://helloclue.com/. Source: over 1 year ago

I came up with the various symbols myself; for fertility stuff my first thought would be to look at what Clue is using these days, if you're drawing a blank (as it were) on anything! Let me know if you'd like to see a more recent/more filled-out version :). Source: over 1 year ago

Can’t vouch for the efficacy because I haven’t used the feature, but the cycle tracking app I use clue has a new birth control feature that’s FDA cleared. it’s by far my fav tracking app and i’ve been a loyal user for years now, so i’m sure their BC function is good too. Source: over 1 year ago

Please check out Clue App on Android and iPhone. This app refuses to sell data and will keep you safe. It's already used by 12 million people, make the number higher! Source: almost 2 years ago