All creams can be used without a brush, just use your fingers. If you’ve got some lying around, try it and see. On the other hand, there are “brushless” or “non-lathering” creams that will not lather with a brush (of course you can smear the cream around on your face, but it won’t make a lather). Experiment and see what you like.
KMF makes a small TSA approved tube that works great with or without a brush.
I’ve travel a couple times a month and have for 20 yrs. Packing a brush is something I’ve always done so I’m not much help. I can tell you that the travel sized Crabtree and evelyn creams and after shave lotions are what I always use and could probably be used brushless although it would be a waste.
Like others have said, any cream will do it. But there are "brush-less" creams specifically designed not to used with a brush. Pre de Provence 63 has a great brush-less cream - though its not labeled that, and for some reason, they say it lathers like a champ when it really doesn't. But it works great and smells awesome. I leave it in my shower for those days when I'm really, really late and have to shave in the shower.
Pacific Shaving Cream from Amazon - less than $6 for a tube.
I just returned home after a month abroad and used a tube of Pacific Shaving Cream with a Feather Popular DE razor. This was a great combo for me. I chose the PSC due to the fact that it applies as a white cream and stays white as long as you apply it correctly. This was important to me as many of the inexpensive tube creams apply as clear, which I do not like.
The PSC provided slickness, glide, cushioning and protection while using the Feather Popular DE razor with Feather Hi Stainless blades. I really only needed 2 passes and a bit of cleanup and I was good to go.
IMO this is very good travel cream, small, light and very inexpensive. Now that I am home I can start using my preferred brushes with the excellent T&H and TOBS creams. And of course, heated in my GP scuttle : ) - luxurious...