Need baby name help.

So we already have a 2.5 year old boy named Zaden and another little one joining us in April. Gender is a surprise.... daddy is Nigerian and I am half Scottish and half Japanese (not that it matters name wise but might help paint a picture and help with name suggestions) we really want something that goes with Zaden, so not common and somewhat unique. But any suggestions will help. Thanks 😊

Z names are great but other letter names are also welcome... especially for a boy