- one2many
- many2one
- many2many
- Related
- Character (Text)
- Multi-line text
- Selection
- Numeric
- Float
- Integer
- Monetary
- Date / Time
- Date
- DateTime
- Boolean (Checkbox)
- Binary (attachments)
- HTML
For more information on the first 4 field types:
The other field types are fairly standard
Odoo now has some good documentation on this: Odoo fields and widgets