Trial and error is your friend with big horses. Find a brand that works well on them and stock up. I see so many posts on social media "ISO of 7" bit" or "ISO of 100 inch blanket." Your first step would be to MEASURE your horse. Just because they are big, doesn't mean that they need giant tack, believe it or not. Also, not all drafts need draft specific tack, and honestly, stay away from it because most draft specific riding tack (I said most, not all) is extremely poor quality. Here is an example: http://drafthorsesaddle.com/product_info.php?cPath=13&products_id=71&osCsid=8ef1005103466af3c37d3b11c6a226a0
A "draft horse saddle" *barf*
Klein has one piece of tack that is actually made for bigger horses, and that is her jumping saddle, a Duett Presto. However, when we're done with the Presto, I don't think I'll get another Duett. I think I'll be looking at a CWD. I have had her fitted by a CWD rep before. They had no problems fitting her and had plenty of options for us. She also has had a Voltaire on before and it was fine. Her dressage saddle is nothing more than a Wintec Isabell. It has the XW gullet in it, and fits us both well so why fix something that isn't broken? Same idea with the Presto, it fits us, and it's really comfortable, so I will keep it until I have an actual reason to buy a new jumping saddle.
She's normal sizes in saddle pads. Her half pad is a Mattes shimable pad and it fits fine.
Klein wears a Micklem bridle for everything. It's their largest size, "large horse", and no she is not on the last buckles of any part of that bridle. Before that she wore a Bobby's bridle, also not a draft specific brand.
She wears breast collars in Oversize (OS) aka Warmblood (WB). Brands that fit will vary.
Boots have been a pain and we are very limited but I have found something that works and bought multiple pairs. Woof Double Locking brushing boots are what works best for her. She is an L in the front and XL in the rear. Polo wraps, she can wear horse size polo wraps no problem. The standard 9' length has never been an issue. Standard no bows and even Back on Track Quick Wraps fit her as well. Keep in mind I keep her feather trimmed too though.
Back on Track Quick Wraps
Blankets, Klein is an 84-86, depending on the brand. Big Fella blankets are popular among the draft community because they are billed as draft blankets with a draft specific wide cut. I bought one, and the fit on Klein sucked. The length overall was fine, but the length of the blanket on the sides was short and she's only 17hh, she's not a big draft by any means. What does work? Amigo XL. Klein and Wes both have Amigo XLs. Wes is a 90 and he is 18hh. The cut and fit are GREAT on the
LOVE the Amigo XLs for drafts!
Back on Track Quarter Sheet.
Back on Track Mesh sheet
Bits, Klein is a 6" in anything with a solid mouthpiece and a 6.5" in anything with a broken mouthpiece. Those can be a bit challenging to find, but they are out there! My personal favorite site to find anything you are looking for in bigger sizes is this place: http://www.thehorsebitshop.co.uk/ Yes, it is from England, but the shipping isn't that much more. They even have a trial program with their bits and the program allows overseas shipping. Shipping doesn't take as long as you might think either.
If you really are against dealing with overseas shipping, Draft Tack is actually probably the best source of variety in the U.S. as far as bits in size 6" and larger. You can find them here, the menu is on the left for different styles: http://drafttack.com/page79.html
Girths, a lot of people fall victim to looking for a "draft girth" on this one too. Measure your horse. Find a girth you like or a style of girth you like and spend some time researching if they exist in the size you need. Klein has all Total Saddle Fit Girths. She isn't even in the largest sizes they make.
Her TSF girth for her jumping saddle.