What I definitely recommend is the use of a beanbag tripod. Especially when taking photos from the car it is of great help because you can put down the lenses, which are usually very heavy, without risking bumps, which can damage the sensitive technology inside. In addition, they are very light and transportable, so you can take them with you anywhere at any time. Especially when traveling by plane, they hardly take up any space and you can save a lot of weight compared to a regular tripod. And actually you can even use them as a pillow.
Many things can be used as filler material. In the beginning, I got myself to this by buying a bag of rice on site (in South Africa I think that was about ZAR 35/2 euros for 2kg of rice) and filling the bean bag with it. That worked well for stabilization, but was comparatively difficult. Later it occurred to me that beanbags contain a filling that is even more suitable: due to their small size (3-5mm) and minimal weight, these styrofoam balls are now the best choice for me. Should you buy some, keep in mind that they really weigh practically nothing, so you don’t have to buy a large amount to fill a bean bag. A large garbage bag is about 50 liters, for the bean bag you probably don’t even need 2 liters (of course, that depends on the model you choose).
I myself currently use three different models that can be bought at amazon.com:
My first beanbag is still with me today. It is particularly flexible and can be used on all surfaces to store a heavy lens. It is also divided into two chambers, so that it can also be used well in the car window. You can purchase it here.
This is of course also possible with my second beanbag, but its fixed chambers are more intended for use in the car.
The LensSack from LensCoat, which is known for its products especially for wildlife photography, is particularly suitable for filming from the car. A tripod plate on which a gimbal head can be mounted can be inserted into the upper chamber of the bean sack. In addition to filming, you can use it to photograph birds in flight particularly well, as such a tripod head supports “pulling”.