According to your profile you are infantry, therefore your next career course is IPSW.
Anything else will depend on what is available in your unit/within local units (that your unit wants to load you on). This could likely include various driver courses (LSVW, MLVW) or ATCIS Op.
That should keep you occupied for the next while. Keep in mind some of those mentioned above are prerequisites for further courses (IPSW for PLQ (Inf), LSVW for Milcots, ATCIS Op for BRP).