Calling a pastor is one of the most important things a church can do. The pastor will set the tone of the church for his entire tenure. To leave that to an outside "talent agency" removes the church too far from the process.
To call a new pastor a church should form a pulpit committee made up of the most spiritual men in the church.
Those men, before doing anything else, should spend time together in prayer. Asking God to open their hearts and minds, and to lead them to the man He would have as their pastor.
They should spend some time discussing exactly what they are looking for in a pastor.
Then they should start to interview candidates. One at a time. It should not be a popularity contest. Each candidate should be interviewed by the pulpit committee, given an opportunity to teach and preach, answer questions from the congregation, then be voted on by the pulpit committee, and if they approve then by the congregation. A straight up and down vote in each case.
If he is not selected, then the next best man on the candidate list should be contacted to do the same again.
And keep doing that until you find the man God wants to be the pastor.
This process does not do much to introduce men looking for a pulpit to the committees, but there are several ways to make it known that you are available.
1. Notify all the churches in the area that you are available for pulpit supply.
2. If you are a member of a church denomination that has local and regional associations, notify them you are available for pulpit supply.
3. If you have a local, regional, or denominational paper or publication put a notice in the paper or publication that you are available.
There is a lot more, but that is enough to think about for now.