I use the baby trend hybrid carseats. They fit in mine across (Atlas) and my husbands (Camry)
Where are you from? As recommendations would vary based on the country. In the UK Axkid Minikid are one of the safest and most compact car seats so would be your best bet
You can join Car Seats for the skittles on fb and they can help you. A group full of experts who will give you correct and safe recommendations