Seeking blessing from righteous people is of two types.
1 – Seeking blessings by asking them to make du’aa’ to Allaah for one. This is permissible, subject to the condition that they be known to be righteous and pious and that they will not be exposed to fitnah thereby.
2 – Seeking blessing through their relics, such as their clothes and belongings, etc. This is not permissible and is a form of reprehensible bid’ah (innovation).