Sky Express and Aegean/Olympic have both launched a (temporary) discount offer with up to 30% or 40% off.
Aegean/Olympic:
https://en.aegeanair.com/flight-deals/offers-competitions/flights-to-all-network/
Sky Express:
https://www.skyexpress.gr/en/flights-up-to-forty-percent-off-april26-en
As always, don't forget to read the terms & conditions.