My first one was a Samsung Galaxy S1 that I got in 2013 and it was a great little device that was easy to open up and repair. It had only 512MB of RAM but that was plenty for basic phone needs, web browsing and running some Android apps like AnkiDroid at the time.
My first was a Galaxy S1 back in 2010 which I rooted and flashed with custom ROMs almost immediately. I remember applying the various generations of Voodoo lag fixes because Samsung used cheap shitty flash storage and a slow proprietary file system. Once the Nexus S came out the dev scene took off because they had almost the same hardware. I had it running up to Android 4.2 or so before it was relegated to sitting in a drawer for good. Unfortunately I don’t know where it is now, if I still had it I’d try to boot it up and see if it still works.