All these mods are open sourced and have licenses to support this. All open source licenses allow the use of their Code/Mods as long as you give the respective credit for that said Code/Mod. All mods have the credit given to their creator via the mod list. The mod list has all authors listed as well as the links to there respective websites.
(There is one exception on this list.... The Portal gun creator tries to say that there mod is protected under copyright to prevent use in modpacks, as it is truly not under a copyright (as that would be illegal due to the actual games Portal and Portal 2), we still use this mod in our pack and just give credit to the respective creator, also this mod if it was copywitten would not be publicly distributed. Until proof of a license to truly prevent me to use this in my pack, the mod shall stay.)
(There is one exception on this list.... The Portal gun creator tries to say that there mod is protected under copyright to prevent use in modpacks, as it is truly not under a copyright (as that would be illegal due to the actual games Portal and Portal 2), we still use this mod in our pack and just give credit to the respective creator, also this mod if it was copywitten would not be publicly distributed. Until proof of a license to truly prevent me to use this in my pack, the mod shall stay.)