Thoughts and a craft idea for
1. Horn of Plenty, aka, "Cornucopia"
2. Making a Cornucopia with a "Praise God from Whom All Blessings Flow" never ending ribbon.
Important Background to Share
Cornu meaning "horn" and Copia meaning "plenty" in Latin (Roman). The tradition of the "horn of plenty" comes from the Greeks and is found in one of their myths. As the story goes, Hercules broke the horn off of a god he was battling who had transformed himself into a ram. After the battle he gave it to his defeated enemy as a peace-offering gift which never ran out. The symbol found its way into Israel and was found in various forms on coins and tombs. According to the Bible, ritual horns were also used as signals to begin holy days, as warnings, and to make announcements from heaven.
In the USA, we use the "Cornucopia" image at Thanksgiving to symbolize "abundance." We seem to have lost its original meaning of "never running out" and peace-offering. (In the craft suggestion below, that's why I'm adding the "never ending ribbon" to the project.)
Related ancient traditions include the use of "drinking horns," to toast or pledge loyalty with. These various traditions are not unlike the use of the ritual "cup of blessing" used at Passover, which Christ used at the Last Supper. Christ's gift in this sacrament never runs out.
I'm reminded of a similar "cornucopia at the well" when Jesus says to the woman, "whoever drinks the water I give them will never thirst. Indeed, the water I give them will become in them a spring of water welling up to eternal life.” A peace-offering indeed.
Cornucopia Craft Project
Here's a cornucopia made using colored foam sheets which are better than construction paper because they look more substantial, and won't tear or fade. It can serve as a Thanksgiving centerpiece and family devotional.

Tips A teacher with a hot glue gun dispensing dabs of glue to fix items on the cornucopia will speed up the process and make the foam adhere much faster than white glue.
Tip: Add a blank "fruit or two" on the cornucopia that kids can invite parents to fill in at the table.
How to add a "never ending ribbon of blessing" to the cornucopia
The addition of a ribbon loop that can be pulled from the cornucopia helps reinforce the corncupia's original "never-ending" meaning. In addition to the typical things kids are thankful for (pets, grandmas, etc), it becomes a place to record things of Godly importance.
How to: On a 12-16" ribbon, students write a scripture verse and series of "things God never runs out of" (Love, forgiveness, salvation, help,) Then they cut a slot in the "mouth" of the cornucopia and slide the ribbon in it. STAPLE the ends of the ribbon together to form a loop. The "endless" ribbon can now be pulled as if it is coming out of the cornucopia -revealing the blessings which continue to flow. Add the phrase, "Praise God from Whom All Blessing Flow" (from the Doxology).
Tip: Allow students to select a thanksgiving verse. Here's a collection of them at Biblestudytools.com (there are many such collections online). Print the verses and let kids pick one to put on their cornucopia or ribbon. For non-readers, write the line from the Doxology.