There are 2 things that come to mind.
One is my bass clarinet/bassoon stand by Hercules. I like instrument stands in general. Each one of my horns has at least 1 stand, so it’s easy to access/arrange in a performance situation. One time while performing with a high school pit orchestra, I even supplied the rest of the student woodwind section with stands for their instruments. But the bass cl/bassoon stand for me is particularly handy. For starters, it’s an excellent deal. When the Hercules was released, the only other stand on the market was 2-3x it’s cost. Not that it’s cheap, but it’s certainly an easier pill to swallow at it’s cost relative to the other stands. And if I feel like I’m getting a good deal, I’m happy. But besides the price, being able to put the bassoon down safely is so nice. Especially for teaching, I like having it out but I may only have one or 2 bassoon students on any given day. And given the size of my studio, it needs to be strategically placed. Overall, I’m very happy with the stand.
Second item is the ForScore app paired with my 12.9" iPad Pro. I’ve been a long time user of reading sheet music on an iPad using ForScore. Early on I used it on a smaller iPad 2 for reading horn band charts. Even though it was a smaller screen, horn charts are relatively easy to read or flip pages. Going to the larger screen is when I really started to use the ForScore app to it’s fullest potential (and still only using a fraction of the features). For starters, being so big you can have 2 pages up in landscape mode which makes it perfect for musicals. It’s also a great practice tool since you can attach an MP3 to the file as well as loop and slow down sections. Perfect for playing along with some of your favorite big band sax solis. I also put several Real Books and have them indexed for easy access and building a playlist.
So what are some of your favorite and useful musical accessories? Items that every time you use them, you’re glad you have it.