Lowe's has way more fittings than big orange. Just a tip, sch 80 unions are about $3.00 less than sch 40 at either big box. I ordered some true union ball valves by Legend from HD and they were cost effective and very well made. Just to cover my bases, I also ordered a Spears gate valve from BRS. It was pricey but also well made. Lowe's has bulk packs of 90 degree sch 40 elbows that are much cheaper than buying them in single quantity.
It all depends on what you are looking for in size, color and quality. The best thing I can recommend is to make a list, plan it out as best you can and then look online. You will probably find yourself buying from multiple sources to get everything you need.
