Working out just to work out isn't the best motivation, and since I'm a sucker for gadgets and new toys, here's a few of my all time favorites.
Simple and practical. I've gone through a dozen apps and this is by far the best. You can customize it to climbing-specific routines and it acts like a to-do list you check off, and it tracks your weights/time/reps/etc.
Tabata Timer App
Another app that's so complicated to get simple. Practical minimalism, down to each stopwatch digit being a separate slider. You don't have to type your time or scroll from 1 to 60. It's the small things.
Adjustable resistance grip strengthener
A++ compared to those donuts. You can adjust from 20-90lb resistance.
Suspension trainer on a pulley
I won't pay $200 for TRX-branded suspension trainers. This $40 version is made on 10mm rope with a pulley. You have to stabilize both sides of your body. It's a climber's training dream! The price is right, and literally all of their products have 4.8 stars on Amazon.
Wahoo heart rate monitor
I do all my HIIT interval workouts based on heartrate, not time. I survive a workout and I can see small improvements in recovery time or max HR, which is more motivating week over week. Don't start the next set until your heartrate is back down into the 150's. After a little bit, you'll know your range and can figure it out without the monitor.
Attach weights to the bottom, get a burn rolling up and down.
Just the right amount of give compared to lacrosse balls. I rolled a few times a day right after surgery.
High-quality, sturdy kettlebells from Kettlebells USA.