Konsole and xterm, although I haven’t had to use xterm in a while. Actually, circa 1997 I used kterm, the predecessor to konsole. ;)
Straight up Linux ttys are also quite common for me. Most old school distros still let you escape to the terminal, with CTRL-ALT-F1 or similar. I haven’t distro hopped in a long time, so I don’t know if other distros still do this.