Generally, the idea is that all of your assets should be in your trust. However, there are a few assets you may not want, or that cannot, put your trust. There may be a valid reason (like avoiding a potential lawsuit) for leaving a certain asset out of your trust.
Typically, assets you want in your trust include real estate, bank/saving accounts, investments, business interests and notes payable to you. You will also want to change most beneficiary designations to your trust so those assets will flow into your trust and be part of your overall plan. Some exceptions may be IRAs and retirement plans.