Formal:
* Furthermore: Adds a point that expands on the previous one.
* Moreover: Emphasizes the importance of the additional point.
* In addition: Indicates a separate but related idea.
* Besides: Suggests something extra or supplementary.
* Likewise: Indicates similarity to a previous point.
* Similarly: Points out a parallel between the two ideas.
Informal:
* Too: Simple and common.
* As well: Neutral and versatile.
* And: Direct and concise.
* In addition to: More formal than "and," but less formal than "in addition."
* On top of that: Highlights the additional point.
* Plus: Casual and conversational.
Specific situations:
* Equally: Emphasizes equivalence or equal importance.
* Correspondingly: Indicates a parallel or matching situation.
* Consequently: Suggests a result or consequence of the previous point.
The best synonym will depend on the specific sentence and the desired level of formality.