Fringe, hands down. An amazing show from start to finish. I also have a soft spot for Warehouse 13, which leans more into the fantastical.
More recently, the first season of Star Trek: Strange New Worlds has been great, and I'm also looking forward to seeing the second season of Severance.
Fringe was great! Some of its episodes to felt like they leaned more towards fantasy than scifi, but it was good enough to make me finish the entire story in a couple of days. Never heard of Warhouse 13 before, will check it out!