Well, when choosing tags, asset registry gave me a hint. Here’s a nasty bruteforce solution: (In case anyone needs it or would like to give me some feedback)
FAssetRegistryModule& AssetRegistryModule = FModuleManager::LoadModuleChecked<FAssetRegistryModule>("AssetRegistry");
TArray<FAssetData> AssetData;
AssetRegistryModule.Get().GetAssetsByClass(FName("MediaTexture"), AssetData);
for (int i = 0; i < AssetData.Num(); i++) {
UMediaTexture* FoundMedia = Cast<UMediaTexture>(AssetData[i].GetAsset());
if (FoundMedia != NULL) {
FileNames.Add(AssetData[i].GetFullName());
Textures.Add(FoundMedia);
}
}
}