There seems to be another gift card (Geschenkarte) promotion, which is indeed 25% off again. It might be aimed only at the German market (because I haven't seen it elsewhere). I think it really is quite good, if you can be sure you will use it. But the booking window is tight (until 14th February). The way I read the rules in German, it says you can redeem it in the period 8 to 14 February for flights up until 31 December. But maybe "Buchungszeitraum" refers to the purchase of the gift card itself, rather than actually booking the flights.
Buchungszeitraum: 08/02/2021 - 14/02/2021.
Er kann bis zum 31. Dezember 2021 verwendet werden, wann immer Sie fliegen wollen.
50 € Geschenkkarte für nur 37 €
100 € Geschenkkarte für nur 75 €
300 € Geschenkkarte für nur 225 €
500 € Geschenkkarte für nur 375 €
https://www.iberia.com/de/Geschenkka...208_de_tarjeta