Reddit mentions of Stud Finder Wall Scanner - 4 in 1 Electronic Stud Sensor Wall Detector Wood Beam Finders Center Finding with Battery and LCD Display for Wood AC Wire Metal Studs Detection (Black)

Lots of others have mentioned great projects, so let me give you a general overview of what you should know, and then you can tackle just about anything.

For every project:

• Watch youtube videos for whatever you want to do until you're pretty comfortable. Make sure the person looks professional. "This old house" is a great resource.
  
• ALWAYS take off jewelry and things like wallet chains. Wedding bands are especially notorious for electrical accidents or something awful called "Degloving." Google if you want to be horrified or have an iron stomach when looking at gore.
  
• Most projects are "Safe" if you know how to disengage and engage the shutoffs and what to watch out for.
  
• Assume whatever you're using is going to spread everywhere (sawdust) or get on things you'd never expect (spray foam on the nice rug 10' away). So cover them or move them.
  
  Electrical:
  
  
• Buy a non-contact voltage tester. It'll tell you if you're about to shock yourself or not. Check it every time you walk away and come back. I also put masking tape over breakers I'm working on just in case somebody walks by and decides it needs to be flipped.
  
• Always work with your right hand only (even if you're left handed). This is to keep a shock from traveling through your heart, which is on your left side of the body. Don't work on a wet/damp surface. Wear thick wool socks and shoes or boots with lots of rubber left on them.
  
  Plumbing:
  
  
• find your whole-house water shutoff, and the shutoffs (if they're there) for the sink or wherever else you're working.
  
• Also, if you do anything with compression fittings, under-tighten them (never over-tighten). Turn the water on (just a bit) and if it's dripping, do a quarter turn and wipe dry with a towel. Repeat until it's no longer dripping. If you overtighten them, they'll leak and you can't undo it without replacing the fitting. It took me 5 trips to Home Depot to learn this...
  
  General:
  
  
• Never climb a ladder without somebody else around. Always take the time to go down it, if you have to fiddle with changing drillbits or something, or have the helper-person take care of it (and hold the ladder when needed). It doesn't matter how good your ladder is, if you're pushing against a wall with a drill, you can easily destabilize yourself.
  
• Buy a deadman's switch that plugs in like an extension cord, and swap it to any saw or cutting device you are using (even the dremel). Alternatively, spend a few more bucks and get a variable speed foot pedal.
  
• Don't do anything you don't feel like you "know" enough to do, yet.
  
• Learn how blades buckle in saws, and about kickback, before using power saws.
  
• Use a GOOD stud detector before going into the wall. If you hit something hard and you aren't sure what it is, back the drill out and take a look. You could be hitting a water pipe, an electrical cable, or are just unlucky and hit a nail in the stud.
  
• Use goggles and hearing protection. Your ears don't feel pain. Power tools are louder and more damaging than they sound like.
  
• Working with chemicals? Use a gas mask (I like a full painter's mask that incorporates eye protection, because they don't fog like goggles can with a mask on).
  
• Working with dust, use a dust mask or gas mask.
  
• If you have gas mask, you have to seal the cartridges or they go bad fast.
  
• Go to Walmart (because it's much cheaper) and buy a gallon of their solvents before working with chemicals. Know which solvent works on what. Buy low VOC mineral spirits (if available), and acetone. Mineral spirits is going to be for exterior/oil paints, shellacs, and stains. Acetone is going to be for spray foam, certain adhesives, etc. Get an empty tin can with a lid for storing the "used solvent." Btw, I reuse my solvent several times, basically as a "prewash." The sediment falls to the bottom.
  
• If you're working with something creating sparks (angle grinder) be aware of where those sparks are flying, have a nearby fire extinguisher, and if you can, dampen the area first (like mop your garage floor). Angle grinders combined with dust, sawdust, and/or scrap wood has started fires.
  
• If working with oil based products/mineral spirits, learn how to properly dispose of things like brushes and rags, they can spontaneously combust if left in a heap!
  
• Be aware that on high-end drills, there's a button that can lock them into "always on" mode.
  
  Tool List
  
  
• Non-contact voltage tester (and other useful items)
  
• 3M Full Face Gas Mask There's cheaper chinese knockoffs. You have to buy cartridges (get a set for dust and at least one set for VOC - aka gasses like mineral spirits and ammonia)
  
• Variable Speed Foot Pedal Can be used like a deadmans switch by fully depressing.
  
• Water/leak alarms for peace of mind or sudden failures
  
• Stud finder with live AC and metal detection
  
• Hearing Protection
  
• Goggles (observe where the vents are and if it looks like dust can easily fall into them) or just use the face mask
  
• Acetone
  
• Mineral Spirits
  
• Metal, lidded, disposal bucket. A paint bucket with a lid also works. Note that paint buckets are a different kind of plastic specifically made to resist solvents.
  
• A large pack of disposable gloves (make sure they aren't something you or a helper are allergic to, eg latex).
  
• Inspection Camera
  
  Projects to avoid as a beginner
  
  
• Major reconstruction (wall removal)
  
• Retaining walls over 1' tall
  
• HVAC
  
• Tile
  
• Traditional wood plank flooring (BUT engineered/click-lock is super easy)
  
• Plumbing that isn't compression fittings or threaded (aka, plex/sharkbite/welding)
  
• Anything on the roof
  
• Anything attached to the outside of your home (where you might inadvertently create leaks or rot in your exterior walls)
  
• Precise woodworking (altering your cabinets in your kitchen)
  
  Projects I'd always recommend hiring out
  
  
• Tile with real stone, metal or glass
  
• Granite anything
  
• Decks (probably, although make sure the deck builder knows how to properly attach to a house. 70% of decks in the USA aren't and are causing rot and damage)
  
• Structural engineering (wall removal/additions, tall retaining walls)
  
• Most HVAC
  
• Solid wood plank floor or refinishing. (Refinishing is possible, it's just a good 10 hours of work per 50 sqft, or more, super dusty, and makes the house pretty unlivable. Easy to screw up. Best to get an experienced pro in to do it quickly).
  
• Anything near your "mains" that feed into your breaker-box (the part coming from the electrical company). Such as replacing the breaker box itself.
  
  Home improvement is very satisfying and not all that hard. Most people have a story of being lazy once or twice and having a near accident. I've been shocked by 120v (like in your wall)... twice. I've had saw blades break. Just be safe for that 5% of the time you're using something dangerous, and never get too lazy to grab the safety gear.

I have tried tons of different stud finders and magnets. The magnets do work, but I found a stud finder that works from Amazon and is the best money I have ever spent in my new house and there is a coupon to save 10% right now on it:

Stud Finder Wall Scanner - 4 in 1 Electronic Stud Sensor Wall Detector Wood Beam Finders Center Finding with Battery and LCD Display for Wood AC Wire Metal Studs Detection (Black) https://www.amazon.com/dp/B07HF92JMR/ref=cm_sw_r_cp_apa_i_GrGSCbEEEP281