Dave Lloyd (former pro, now a regular on the Sportive scene) swears by the Rotor cranks and Q-rings as well.
Biopace never really took off and (as mentioned breifly above), Shimano quite famously got the design the wrong way round, the oval should have been turned by 90 degrees.
Q-rings can be fitted to any chainset and are adjustable for your preference, it’s advised that you first use them in their most ‘gentle’ orientation before turning them to the ‘max power’ orientation once you’re used to them. Rotor cranks are those god-awful heaps of shite with a cam on them, it’s designed to minimise the ‘dead spot’ when pedalling, basically it allows you to be a lazy pedaller and the cranks will make up the difference. Unfortunately it feels dreadful under power and especially when cornering, it also weighs a fair bit more than Dura-Ace/Record/Force*
*delete as applicable