Libraries and book stores usually have anthology sections. Once you find an author you like, you can usually find more of their shorts. As a kid I always bought a ton at used book stores. With more modern stuff (00s and forward) you can usually find a lot of it online once you know the authors you like. The collection you read has a nice range of styles so you’ve got lots to experiment with it!
Analog: Science Fiction and Fact
A paid print and digital magazine I used to subscribe to. I'm only not currently subscribed because I had fallen literal years behind and couldn't keep up. Includes not only fiction but science and futurism essays.
Clarkesworld
A paid digital and print magazine, and free podcast. I would listen to this podcast more but they offer no description and I can't commit to an hour or story time just based on a title.
Asimov’s Science Fiction
A paid digital and print magazine. Tends to have bigger names than Analog and Clarkesworld.