Common words:
* Roi (King)
* Rose (Rose)
* Rouge (Red)
* Rêve (Dream)
* Rien (Nothing)
* River (River)
* Rire (To laugh)
* Rue (Street)
* Réveiller (To wake up)
* Répondre (To answer)
Less common words:
* Rafraîchir (To refresh)
* Raison (Reason)
* Reconnaître (To recognize)
* Réduire (To reduce)
* Réfléchir (To reflect)
* Réussir (To succeed)
* Rompre (To break)
* Rouler (To roll)
* Régler (To adjust)
* Rêver (To dream)
Words with "R" in the middle or at the end:
* Chercher (To search)
* Parler (To speak)
* Porter (To carry)
* Aller (To go)
* Penser (To think)
* Changer (To change)
* Manger (To eat)
* Fumer (To smoke)
* Vivre (To live)
* Passer (To pass)
This is just a small selection, and there are many more words in French that begin with "R".
Do you have a specific topic or theme you'd like words for?