How do I update all beige bathroom with what color towels?

I think something with fall colors like orange, rusty color, yellow orange or even a deep blue.

Just find a patterned fun shower curtain with several colors that makes you smile. Use the different colors in towels, add art and a rug.

Pick your favorite. No one can guess what your favorite colors. Pick two that YOU like and mix and match, like dark blue and turquoise, or dark green and light green, even black and white would go with tan and give it a classy look.

I love black and white. I think a buffalo plaid shower curtain and black or dark grey towels would look beautiful with a bone colored room. I love neutrals and use them throughout my house. The color pallet would be like I have in my living room in the photo below.

A melon orange and turquoise would look really fresh. A bolder look might be navy and a deeper orange.

I'll opt for forest green and bright lemon yellow for accent spots -- be sure the green isn't 'olivy', but more to the 'blue' side of green ...

All beige is a great neutral background. You can go more feminine with pink and silver, or moss green with some plant inspiration. I also like soft blue for a beach look.

I agree that black and white would make this area into a spa-like retreat! Then, pop just ONE color in -- like blue for even more serenity.

If you can find a multi-colored curtain with many colors this should resolve your issue. After purchasing the curtain, then take a color from the curtain and buy the towels to match.

Teal or seafoam green would be pretty.