Alternative to LL?

That.

For height gain, lifts. Glucosamine supplements and yoga can help with sitting height. Anything else is decades away.

For size gain, bulk up with supplements (protein, weight gainer powders) and hit the weights 3-5 times per week, focusing on one muscle group per one hour session. Max out with heavy weights then drop down; this way you gain size, not just strength. Eat proteins like chicken with veggies and rice. Some good advice for quick visual gains.

For a change in perspective, traveling to areas with lower height averages.

For self acceptance, therapy.

If you have specific, severe spinal conditions:

https://sinicropispine.com/gaining-losing-height-after-spine-surgery/

Coming out in our lifetime:

https://www.quora.com/In-the-future-will-there-be-a-way-to-re-open-growth-plates-after-puberty-ends

http://www.naturalheightgrowth.com/2016/10/26/alexander-teplyashins-research-increases-length-finger-bone/

When companies and clinics specializing in this pop up, it will be a good investment. Too many people desire more height.

Below 25 try hgh
Or mk677 or Hexarelin or CJC No Dac

Actually only temporary alternatives but no lifelong alternatives so forget anything else except LL.
Hanging is likely to augment your spinal discs to elongate your trunk for a lifetime cuz I've ever heard from one friend tolding me he was a success in hanging to grow taller and his X-rays even astonished his radiologist.His X-rays manifested his spinal discs had been augmented abnormally and he obtained 5.5 growth in the end.
I heard of this anecdote 4 yrs ago and I've deleted him since then so it's impossible to add him back into my QQ friend list.Also his X-rays were not  archived in my phone.

I think other than LL, which is painful during the rehab, is something that can be injected to your heel to guarantee you a life long height. But it's only 2cm added by maximum, and probably already existed in some countries.