There are two recent Iberia partnerships worth knowing about. You will need an Iberia Plus account to earn Avios points with these, but they can be quickly transferred across to an avios.com or British Airways Executive Club account using the ‘Combine My Avios’ feature online. The only condition is that your Iberia Plus account must have been open for at least 90 days before you can transfer in or out of it. I have already joined up.
Iberia Express is the new low-cost airline formed by Iberia to compete with Ryanair etc, and has been the cause of the recent industrial action by Iberia staff. Iberia Express flights earning NOTHING if credited to BAEC, but they do earn in Iberia Plus at the same rate as standard Iberia flights.
Current overseas destinations are Dublin, Amsterdam, Edinburgh, Riga, Naples and Mykonos, all from its Madrid hub. (I understand that you WILL earn Avios in BAEC if you book an Iberia Express flight under its BA or Iberia codeshare via ba.com or iberia.com but you will not earn anything in BAEC if you book it directly via Iberia Express’s website.)
Sixt is now a car rental partner with Iberia which is handy as it is not a BAEC partner. (Here is my previous overview of car rental earning opportunites to gain Avios, although Europcar is no longer a BMI partner.) Until 31st August you earn double Avios points with Sixt when credited to Iberia Plus. Standard rates are 300 per day for a Standard or Tiny car and 400 for a Compact or larger (less 50% if booked on a corporate rate code), with a maximum of four days. During this promotion, the maximum earning is therefore 3,200 miles (400 x 2 x 4 days).