QUESTIONS FOR PRACTICE
One of the most important thing to have for practice is questions to read. Reading old questions will help players get a sense of what the canon is--the topics that come up more often. Luckily, there is an online archive of questions that have been used in past years.
The Quiz Bowl Packet Archive contains a lot of old tournaments. Most of these tournaments are classified by difficulty. A (1) is for novice-level high school tournaments, and a (2) is for regular high school difficulty tournaments. Anything above that is primarily for experienced teams, or for preparing for national tournaments.
There are also a smaller number of middle school tournaments that have been released, and they can be found here, too.
In addition to these public domain question, NAQT produces tournaments that it does not release to the public domain. You can get copies of their questions either by attending their tournaments, or by purchasing copies of old tournaments from them. You can buy them from NAQT's website. (They also sell other materials, like warmup questions and frequency lists.)
NAQT does have one sample question pack from each type of tournament that they run. You can view these sample questions on their website, but if you want more questions, you will have to purchase them from NAQT.
Because quiz bowl is played across the country (and even across the world), there are several online sites where players, coaches, and others can go to ask questions, share study tips, and get feedback. This is especially useful in more isolated circuits, like Idaho's.
The High School Quiz Bowl Forum is one of the oldest online communities for quiz bowl. It is a great place to go if you have questions on running practice, fundraising, or anything that other quiz bowl coaches may have experience with.
Discord has become a popular way for quiz bowl players to communicate with each other. People will often read question packets to players online. (Note: While these Discord servers are moderated, there may still be some objectionable content that slips through.)
The quiz bowl discord server is https://discord.gg/Vzhb6p8
IQAT has set up a server for talking about quiz bowl in Idaho, https://discord.gg/6PtXnRR
OTHER PRACTICE RESOURCES
There are a couple of sites that will "read" questions to you by displaying it on your screen word by word. This can be useful for players to study packets outside of practice.
Quizbug is a site that will "read" questions from old tournaments to you. It is a great way to get practice outside of practice so that players can have questions read and practice buzzing in on where they think they might know the answer. (The interface may not be intuitive at first, but it's pretty easy to get to know. The 2,4,6,9 box is for difficulty, where 1 is easiest (middle school), 2 is high school novice, and so on, up to the hardest difficulty of 9 (masters/open).)
Protobowl is a site that uses old question packets and "reads" them to players online. Unfortunately, the question set it draws from has not been updated, so heavy use of this site will see questions repeat. The main advantage to this over Quizbug is that it is multiplayer, so your team can practice together on it. Unfortunately, that also means that there can be people who abuse this unmoderated site, so it's best to create a private room to use. This can be done by just typing some word after the URL, as I've done here by creating an "Idaho" room.
Also, the QuizDB site is great for looking up a lot of questions on a specific topic or clue. (Quizbug uses the QuizDB database for its question selection.) aseems DB is also useful for this purpose. It has more tournaments in its database, but less metadata.
QUIZ BOWL ORGANIZATIONS
NAQT is a company that writes questions to use in quiz bowl tournaments. NAQT also sponsors several national championship tournaments at various levels. They also have other resources on their site--some sample NAQT questions, scoresheets, a set of comprehensive and abbreviated rules for quiz bowl, and so on.
PACE (Partnership for Academic Competition Excellence) is a non-profit organization whose mission is to support quiz bowl across the country. PACE also writes and hosts the National Scholastic Competition (NSC), one of the national championship high school tournaments.
ACF sponsors and edits three college-level tournaments: ACF Fall, ACF Regional, and ACF National, which is one of two national championship tournaments for colleges. ACF tournaments are generally packet-submission tournaments where teams competing in the tournament submt question packets, so ACF also has some good resources for question writing on their website.
NHBB (National History Bowl & Bee) produces questions specifically about history. (That's not to say that there's no literature, science, etc., because these all have historical context, too, and will come up in questions.) They also sponsor a national tournament. The NHBB game format is different from standard quiz bowl formats.
IQAT (Idaho Quiz and Academic Teams) is a non-profit whose mission is to promote and support quiz bowl in and around Idaho.