To be honest, I think your current plants look great. Far more interesting and attractive imo than those sterile spiky things. But there are many plants that would give that effect. To recommend some we’d need to know your geographical location.

Sample plants look like Dianella, aka flax lily. If you live in at least a zone 7, they can work for you. But as floral noted, there are many other choices for colder locations.

Hi there !
Thanks for the reply ;) I'm in zone 9b and 10 a

Thank you floral _uk !