What are some alternatives to vertical slats for a sliding patio door.

Curtains

I had a curtain rod installed several inches on either side of my sliding door, with a support rod in the middle, hung above the doors. I loved the curtains with grommets because they slid easily out of the way. I replaced the sliding door with french doors, but, still have curtains, only now, a panel for each door mounted on the door. I've also used bamboo shades.

My mother always had curtains and sheers for hers, she mainly just used the curtains for show and closed the sheers to keep some of the sun off the carpet and furniture. She put them up on the rods so that the door she used to go on the deck was uncovered first.

If u don't need "privacy" a valance could be an option. Horizontal Blinds of closely woven fabric, one for each pane looks nice. I have two bamboo shades hung and since we have blustery winters I have another rod with insulated drapes that I close during cold months. Make sure blinds are hung high enough that when rolled they don't interfere w the door sliding

I have a curtain that has a one way drawstring

Drapes with sliding top, possibly grommets for easy sliding, and tie backs to keep it out of the way when you need to get in and out. Buy them wider than you need so that they can be put off to the side when not in use.

I’ve tried one wide drape. It doesn’t work very well because you need a support in the middle of the rod, therefore you can never open the curtain far enough. So, definately go with two panels wider than the door as suggested if you go with drapes.