preallocate list in R
vector can create empty vector of the desired mode and length.
x <- vector(mode = "list", length = 10)
To expand on what @Jilber said, lapply is specially built for this type of operation.
instead of the for loop, you could use:
x <- lapply(1:10, function(i) i)
You can extend this to more complicated examples. Often, what is in the body of the for loop can be directly translated to a function which accepts a single row that looks like a row from each iteration of the loop.