Favorite obsolete formats.....

Wax cylinders...a technology that literally dissolved.

8 Track tapes - flimsy construction but 1/4 inch tapes running at 3 3/4 ips sounded pretty good in my 69 Chevy Malibu. After that, TDK premium cassettes playing my homemade compilations sourced by my Dual 1215 turntable and Shure (?) cartridge and recorded on one of the first Nakamichi 1000 cassette decks with Dolby. Played on my then home system  - Kenwood 5150 Receiver through KLH 17 speakers connected with zipcord - and in my  cars with a Sony cassette player hooked into the cars' stereo systems and transferable between the two cars. One vehicle was a 1972 VW bus so I wore Beyerdynamic headphones (which I hooked up to the player myself) to drown out the engine and road noise. Wonderful memories as I played Pink Floyd's The Wall as I crossed the Golden Gate bridge every morning on my way to work or Moody Blues as I drove through the Jasper Provincial park in the VW when snowing in September.

Worst of the current bunch? Darko and What Hi-Fi are the two that immediately spring to mind.

Yep, Darko seems to be more concerned about appearing cool & hip. Reviewing equipment playing mainly electronic music...yeah, whatever. 

There are plenty of bands releasing albums on cassette & a few synth wave artists releasing albums on mini disc.

Cassettes and mini discs...I still use both, so in my world not obsolete. 😁

Elcaset.   The convenience of cassettes with the sound of reel to reel.
I couldn't afford one at the time, and now I can't think why I'd want one.