I have an old missal from the 1940's and it contains wonderful prayers for both before mass and after.
After communion I always pray the Anima Christi as translated by Cardinal Henry Newman. someone mentioned about memorizing and this one, with it's poetic rhymes worked for me:
Soul of Christ, be my sanctification;
Body of Christ, be my salvation;
Blood of Christ, fill all my veins;
Water of Christ's side, wash out my stains;
Passion of Christ, my comfort be;
O good Jesus, listen to me;
In Thy wounds I fain would hide;
Ne'er to be parted from Thy side;
Guard me, should the foe assail me;
Call me when my life shall fail me;
Bid me come to Thee above,
With Thy saints to sing Thy love,
World without end.
The other prayer that I love is the Prayer of Thanksgiving for communion, by Thomas Aquinas:
I render thanks to Thee, O Lord, holy Father, everlasting God, who has vouchsafed, not for any merits of mine, but of Thy great mercy only, to feed me, a sinner, Thine unworthy servant, with the precious Body and Blood of Thy Son our Lord Jesus Christ; and I pray that this Holy Communion may not be for my judgement and condemnation , but for my pardon and salvation. Let it be unto me an armor of faith and a shield of good purpose, a riddance of all vices and a rooting out of all evil desire; an increase of love and patience, of humility and obedience, and of all virtues; a firm defense against the wiles of all my enemies, visible and invisible; a perfect quieting of all my impulses, fleshly and spiritual; a cleaving unto Thee the one true God; and a blessed consummation of my end when Thou dost call. And I pray that Thou wouldst vouchsafe to bring me a sinner to that feast, where Thou, with Thy Son and Thy Holy Spirit, art to Thy holy ones true light, fullness of blessedness, everlasting joy, and perfect happiness.
Through the same Christ our Lord. Amen
Lastly - I have a holy card in my missal from my Dad's funeral with the prayer attributed to St Francis.
Lord, make me an instrument of your peace;
where there is hatred, let me sow love;
when there is injury, pardon;
where there is doubt, faith;
where there is despair, hope;
where there is darkness, light;
and where there is sadness, joy.
Grant that I may not so much seek
to be consoled as to console;
to be understood, as to understand,
to be loved as to love;
for it is in giving that we receive,
it is in pardoning that we are pardoned,
and it is in dying that we are born to eternal life.
- St Francis of Assisi
After this I fairly "float" out of Church on a wave peace and joy.