Dead or alive: Operational transconductance amplifier
Not quite dead, it seems. Though Digikey lists only 49 of them, out of a total of 30 300 operational amplifiers, that's not even 1 %. Several datasheets are at least 5 years old, but the TI OPA861 datasheet had a recent update a year ago.  

The good old LM13600/13700 also seems to be still alive: still available from two different manufacturers: NJR (datasheet 2006), and TI (née National, datasheet 2004).  

The OPA861 lists as typical applications:
• Video/Broadcast Equipment
• Communications Equipment
• High-Speed Data Acquisition
• Wideband LED Drivers
• Control Loop Amplifiers
• Wideband Active Filters
• Line Drivers