I’ve often found good training videos, first aid information, etc. in online horse magazines and sites. Here are a few of them. As with all free horse advice, remember it is worth what you paid for it! Use your own thought and judgment about each topic to make the right decision for you and your horse. These are commercial magazines (they are selling things), but they have not been pestering me with emails, and I often enjoy their educational pieces (and yes, I sometimes buy things too).
Horse Link (my favorite)
Hitch Up Magazine (horse trailer tips, trailer loading, and trailer safety)
Stacy Westfall (join as a member to see training videos)
My favorite video