So, let's just start off with saying "I know I'm stupid, but I feel I did the right thing". SO essentially I sold one of my heart horses to an older lady with lots of $$$ that will take the BEST care of him. Any other circumstance, this would be different. 
He is essentially sold, the money is wired to my account; HOWEVER, I signed an agreement that I would keep him till the 1st of the year due to her traveling for the holidays and not wanting to leave him alone as soon as he gets there. I agreed and frankly don't mind him staying for a bit because I love him! I was stupid and electronically signed and said that if he dies or seriously injured himself between now and then, I would refund her money and keep the horse (essentially I own him until he's dropped off on January 1st). Yes I'm dumb, but this home is perfect for him, and the odds of something happening in these 3 weeks are slim. I doubt the contract would hold up in court anyway, but that isn't the point.

WHAT I NEED HELP WITH!! If I have a horse I like between now and then, is there any advice someone would give me when going to pursue a horse? If I like one a lot, should I offer a non refundable down payment to hold the horse till after the 1st for me?? I obviously don't want to buy a horse while my one is still technically pending till I drop him off on the 1st. That could be catastrophic if something DID happen and I bought a horse for 10K and I don't have any money to send back...

advice would be great! 

If it were me, 

I wouldn't even look till that one was gone, money or not because of how you did that.  Odds maybe slim but they are not zero, so if you end up refunding that money, you would loose your deposit. I guess I figure it all happens for a reason, and so if every thing goes according to plan, the perfect horse will come up after :) 

What she said.

I'd wait for the deal to be completely finished. 

I would have written the contract so the sale was complete as of the sale date. I then would have had a separate boarding agreement for the time period until January 1st. 

I second what CindyT said. It's not that long until the agreement is done. Enjoy the holidays and start looking after the new year. I would be more concerned with bringing a new horse onto the property and causing the almost sold horse to get hurt or sick. 

Nope don't do it. The universe isn't that kind. Just a false hope. Don't ever put yourself  between a rock and a hard place. Keep your money.