MCSTACKER is the absolute best website to go to for generating Minecraft commands. I seriously cannot recommend them enough. Minecraft Tools seems like the stone age when compared to MCSTACKER
The only downside to MCSTACKER is that it does not have a rich text editor, unlike websites such as Minecraft Tools and gamergeeks.
Also, consider turning off your adblocker when visiting the site. The site is fully usable with ads, and I've never had a problem with it.

While not always being up to date and having as advanced command generators as MCSTACKER, gamergeeks offers a more intuitive UI and has some extremely useful features. gamergeeks has a command that will instantly give you all of the letter and number banners, and for making custom items, it has a rich text editor, which is much easier to use than MCSTACKER.

Florr.io is one of my favorite IO games. I found out about it through diep.io (which is also a great IO game that I played for most of my childhood) To describe the game in a few sentences; you are a flower and you have petals that you need to use to kill enemies, mostly bugs. You can craft petals with five of the same petal to get that petal of a higher rarity, but crafting chance decreases with each rarity.

WARNING: this game is multiplayer and contains a chat feature where swearing is allowed.

I don't really know how to explain this site, so here's my best attemt. It's basically a website built around the newspapers of an alternate universe. It may not look like much but you seriously need to read all of the newspapers, they're absolutely amazing.

This is basically just diep.io expanded. Really cool and good.

my dad's website where he documents a bunch of books he reads.

Really cool website I found that captures the old web really well. (although I wasn't around for the old web so I guess I have no idea) Either way it has some cool stuff on it.