As well as Section 140 and voting on the Development Plan, councillors have a role in the compilation of the Record of Protected Structures. Recommendations from planners/DEHLG/members of the public must be voted on by councillors, and decisions to refuse Ministerial Recommendations (another name for the work of DEHLG, really) must be accompanied by explanations. I think this rule was introduced to give councillors the feeling of involvement, i.e. to avoid the perception of them being sidelined', but it has been problematic in its application.
The role of councillors in planning generally comes under the heading of 'Reserved Function' as opposed to 'Executive Function', the latter being the name given to non-councillor powers. If you do a search on http://www.irishstatutebook.ie
for 'Reserved Function' in the Planning and Development Act 2000 you might find more examples.
Councillors have been known to extend their remit beyond the powers given to them under the PDA 2000, but I presume you're referring only to legal involvement in the planning process...