Depends on your budget and space. We invested in a Peloton bike and now the Tread (their treadmill) between the two of us we use it daily and have been for 8 months. They have digital subscriptions if you want to buy or already own other equipment and want to use their content. They have a variety of spin classes, running, bootcamp, walking, strength, yoga, meditation, and cardio (like short cardio circuit) classes. It has been life changing for us after having our son.

Other options are Beachbody OnDemand and Blender

Your kids, depending on how old/heavy they are.

I benchpress kids, do overhead lifts, lifts straight in front of my shoulders, airplane (lie on my back, hold their hands, my feet cradle their hips), shoulder carry, piggyback carry, fireman carry, hold them upside down with my arm under their bent knees, etc. Any thing the requires them to be somewhat still teaches them control, and it teaches you to compensate for wiggles (especially benchpressing kids!).

I really like my bosu ball. The videos that came with it are cheesy but there are lots of exercises you can do with it. And it's not as expensive as a lot of things on this post!

Peloton is amazing for cardio workouts. I started out using the app with a basic spin bike I got on Amazon, and I streamed the app to an HDTV I have set up in my basement. I used that set up for about a year and a half, and then upgraded to the Peloton bike. I still use the app/TV set up to stream their bootcamp classes, which I do with an old treadmill, and their floor content, which are basic strength training workouts which I do using a large workout mat, free weights and a resistance band. Their bootcamps are excellent! I would love to buy the Tread but I’m going to stick with my old treadmill for now since the Tread is so expensive.

If you are looking to focus on strength training workouts, Peloton probably isn’t the way to go, since their longest strength-only workouts are 20 minutes in length, and they only started offering these a few months ago. I’m really hoping they start adding more strength-only content as they continue to diversify their content offerings.

I also use the HasFit.com app and the Nike Training Club app, for strength training workouts, for days when I want to do strength-only workouts that are longer than 20 minutes. I've also heard great things about the Street Parking App, which is basically an at home crossfit workout, but I've never tried it.

IMO you don't need anything.

I got into great shape last year doing this:

https://well.blogs.nytimes.com/2013/05/09/the-scientific-7-minute-workout/

The key is consistency. Do it every day. The beauty of the 7 minute workout is it takes away excuses. We all have 7 minutes and a chair. You can even do it while you are watching kids.

I use an app on my phone to keep track of the timing.

You can go a long way with:

A Peloton (I know it's expensive, but it really does help me to have the instructor videos and the linked metrics because there is no planning or decision-making - I just get on and try as hard as I can to meet the cues for 45 min)

After you Peloton, stretch and do lunges, squats, push ups and planks.