To indicate sequence or time:
* After
* Afterwards
* Next
* Following
* Subsequently
* Later
* Thereafter
* Simultaneously (for actions happening at the same time)
* Meanwhile (for actions happening concurrently but not necessarily at the same time)
To indicate consequence:
* Therefore
* Thus
* Hence
* So
* Consequently
* As a result
To emphasize contrast:
* But
* However
* Nevertheless
* Yet
* On the other hand
To indicate a change of topic:
* Now
* Moreover
* Furthermore
* In addition
More informal alternatives:
* And
* After that
* Next up
* Right away
Choosing the best alternative depends on the specific situation and the tone you want to convey.