Contrast: however, but, nevertheless, though, even though, unless, even if, on the contrary, despite
Cause/result: so, therefore, hence, consequently
Comparison: similarly, by contrast, compared to, equally
Summing up: firstly, secondly, moreover, as well, lastly, additionally, it isn't the only
Conclusion/summary: all in all, in conclusion, as a result, in brief
Downplaying/putting into perspective: to be honest, by the way, rather than, as a matter of fact, still
Confirming/extra information/emphasis: indeed, as a matter of fact, what's more, in other words, in fact
Examples: for instance, take..., when...