If there's no signup and it's free, you have to very wary on what the "trick" is, because nothing is truly free. Most of the potentially useful ones looks like trial with locked features.
It’s a tool to brainstorm and vote on ideas.
We did so because we are using it ourselves and the resource usage is so low it doesn’t cost us more to share it with others.
For example: https://techletter.app – I use it to construct my newsletters. Markdown with a few customizations into HTML for WYSIWYG editors. It’s cheap enough to run that I don’t care if others use it. I think the AWS credits add up to $3/mo.
facebook, google, simpleanalytics, stripe, sentry, checkoutpage
Once upon a time I thought about trying to monetize, but meh. There’s bigger fish to fry
There should be separate categories for FOSS and no-hidden-monetization tools v.s. the other fly-in-the-soup tools where you have to drink around the fly...
Besides, free online tools with closed source server-side components are fundamentally different than open source tools.