I was going to edit my other response but I'll just make a new one so OP sees it.
Calum Raasay , out of Scotland, makes some outstanding historo-scientific videos. He travels around quite a bit too.
Another that I haven't seen mentioned is Our Own Devices , he actually used to write for Simon Whistler. Most of his videos are shot in-studio, like Technology Connections and Joe Scott, but he also ventures out into the field for special projects. It's a similar mix to what you'd see on Forgotten Weapons.
Some suggestions I haven’t seen yet, not all of which perfectly map with Tom Scott but are still good! At least the first five of these are also available on Nebula.
Answers with Joe (starring Joe Scott. No relation, but a similar name!)
Wendover / Half as Interesting (two channels with a different vibe, but the same guy)
Mustard (cool airplane and other vehicle stuff)
Innuendo Studios
Legal Eagle
SciShow
Shaun (basically a podcast, but the guy is quite smart and he does a fantastic job considering how boring he sounds! 😂)
I heard Cary Huang (known on YouTube as carykh) does some cool STEM related stuff, and... I guess some kind of live competition as well? It's too late for you to join it though.
Mark "Hyce" Huber is a major rail fan, and does a bunch of related stuff. Works at a railroad museum, used to work for a modern freight railroad, has been involved in the rail sim world, and does educational, usually railroad and train-based videos on the Google video scented advertising platform.
Hyce and some of his buddies actually borrow the format of Citation Needed/Two Of These People Are Lying during their "3/4 of an idiot show." Just watch out for the Mystery Citrus!
There's a video about a rail replacement helicopter in which Tim states that Tom wanted to do a video about it. But he was busy at the time, so they sent the tip to Tim instead.
I never discovered Tom Scott until his announcement that he was taking a break which many other channels made videos on. Looking through them, as well as seeing the suggestions, I can kind of get the gist of the channel. Suggestions I haven't seen yet:
Climate Town - climate and environment related
Rebecca Watson - science and critical thinking
ContraPoints - philosophy related
Adam Conover - Currently more politically oriented but Adam Ruins Everything was more general
I'm kinda surprised no one's mentioned them yet; but if you wanted a long-winded version of Tom Scott with a focus on technologies, take a look at Technology Connections
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