I go for:
Dallara GP2/08 (2008-2010) (because of Formula 1 2005-2008 aerodynamic baseline + beautiful front and rear wing + beautiful winglets)
and
Dallara F2 2018 (2018-2023) (because of beautiful rear wing, front nose, front wing, and sloppy front impact protection structure)
To be honest, Dallara GP2/11 GP2 Series chassis car design was ugly because of nosecone too resemble the Donald duck mouth and uglier higher and narrower rear wing.
How about yours?