Anyway, anyhow, at any rate, at least
These expressions can mean ‘what was said before doesn’t matter’.

I don’t know what time I will arrive. Anyway / anyhow / at any rate I will
be there before 10 o’ clock.
What a horrible experience! Anyway / anyhow / at any rate we are safe, that is the main thing.

By the way, Incidentally, all right, now, OK
These expressions are used to mark a change of subject.

Alice wants to discuss a few things with you. By the way / incidentally she
has quit her job.

Firstly, secondly, thirdly
These expressions are used to show the structure of what we are doing.

First(ly) we need to rent an apartment. Second(ly), we need to find work.
And third(ly)…

Note that firstly, secondly, lastly etc., are more formal than first, second, last etc., and are more common in British than American English.

Morever, what is more, in adddition, furthermore, besides, on top of that

These expressions are used to give additional information.

They are desperately short of food. In addition, they need doctors and
medicines.
Laptops are getting cheaper all the time. Furthermore they are becoming more powerful.

On the whole, in general, broadly speaking, by and large, to a great extent

These expressions are used to introduce generalizations.

On the whole, we had a nice time.
In general, few people are satisfied with their life.
In most cases, people will be nice to you if you are nice to them.

I think, I feel, I reckon, I guess, in my opinion/view etc.

These expressions are used to make opinions sound less dogmatic. Note that I think, I feel and I reckon are informal. I guess is used only in American English. The expressions in my opinion/view are formal.

I think you should give it another try.

I feel you are making a mistake.

In my opinion it would be better to discuss our concerns with them.