Does anyone have any good resource packs for 1.13 which do not change the look and feel of the game too much?
1.13 isn't even out yet, so it's safe to assume that there are no resource packs for it yet.
Please be patient. Resource packs are VERY time-consuming to create and 1.13 has a few fairly major changes to how things work. New and updated packs aren't going to just pop up over night. Usually not even within the first month of release. Particularly because there are major changes, many people including myself also aren't going to actually start working on updates until there's some certainty that the format isn't going to change again before release.