For conditional statements:
* Whether - Often used when considering two possibilities
* Provided that - Emphasizes a condition
* In the event that - Formal, indicating a specific circumstance
* Suppose that - Indicates a hypothetical scenario
* Assuming that - Similar to "suppose that"
For expressing doubt or uncertainty:
* Maybe - Suggests a possibility
* Perhaps - Similar to "maybe" but slightly more formal
* Possibly - Indicates a chance of something happening
* Could - Implies a possibility or ability
For introducing a reason:
* Since - Introduces a reason for something
* Because - Another way to introduce a reason
* As - Can also introduce a reason, but can have other meanings
For introducing a result:
* Then - Used to introduce a consequence
* Therefore - Indicates a logical conclusion
The best synonym to use will depend on the specific context and the desired tone.