Jumbo Cryptic

[Ameld]

I have really struggled with one but I am nearly there. I doubt I shall arrive without help though. There are three clues which I can't get. The first is
Producer of powerful number: there's nothing more catchy, perhaps gripping millions.
I have o?i?m / ?o?p? And the only thing I can think of is " opium poppy". This sort of meets the beginning but I cannot work out anything else.
The next one is
Little support for driving on motorway ultimately.
I have t?e?y which suggests "teeny". I can see tee and the final y but how does the n fit in?
The final one has me completely stumped.
Fee, mostly, is what one works for
I have I?o?/ m?n?r but I have no idea what might fit.

I should be really grateful for guidance please.
Alan Meld

[Lie-in King]

Mamya has parsed the 1st here -

http://www.theanswerbank.co.uk/Quizzes-and-Puzzles/Crosswords/Question1561860.html

Teeny - 'tee' (little support for driving [golf]) + '(o)n (motorwa)y' (ultimately)

Iron-miner - 'Fe(e)' mostly, is the symbol for Iron

[Neveracrossword]

Teeny - Tee +the N at the end of On and the Y at the end of Motorway.

[Ameld]

Thank you so much, Lie-in King, Neveracrossword and Mamyalynne. I can see each one now but my previous assessment was right: I would not have got them without your help. The iron/fe answer would certainly have defeated me! Clever though!
Again, to all of you, many thanks
Alan Meld

[Mamyalynne]

It's good to help out Alan.

[Lie-in King]

Happy to help, Alan :-)

[Ameld]

I'm glad you enjoy helping. I think you are all amazingly generous!
Alan

[Mamyalynne]

I know I've needed help a lot over the years so sharing is all part of it.