Sibillini (bikepacking.com)

www.sibillinibikepacking.it/web/eng/index.htm

bikepacking.com/routes/bikepacking-sibillini-italy/

"Surrounded by the spectacular mountains of Marche region, Monti Sibillini National Park offers a 3-4 day bikepacking loop around one of the most impressive and spectacular massifs on the Italian peninsula. The route follows gravel roads and singletrack trails through enchanting and timeless landscapes where many myths and medieval legends began."

Apennino Bike Route (full, with minor mods)

with some minor changes to avoid busy roads

some portions shared with Ciclovia dei Parchi della Calabria 

Drau cycle route

www.drauradweg.com/en/

"The south side of the Alps. From the Dolomites to the Pannonian Plains

From the world-famous Drei Zinnen at Toblach/Dobbiaco, cycle alongside the Drau through the sunny town of Lienz, from the beautiful Upper Drau to the cultural town of Spittal, from the lively town of Villach to the landscape gardens of the Rosental Valley, from the gunsmith town of Ferlach to the dreamy Jaun Valley, from the border towns of Lavamünd and Dravograd to the university city of Maribor, where the Pannonian Plains begin and you finally reach Varaždin."

Andalucia: Seville-Cordoba-Cazorla (northern half)

www.cyclingeurope.nl/routes/andalusie/gps.php

Rhine route (via cycling thread)

www.cyclingthread.com/switzerland-and-rhine-cycle-route-one-of-most-beautiful-in-europe

The Rhine Cycle Route in Switzerland begins in the Swiss Alps and follows the Rhine River to the North Sea. The route offers scenic views, including the Swiss Grand Canyon and Lake Constance. Cyclists can travel by train to the Alps and secure bike reservations for the journey.