Euthymius the Great (377–473) was born in Armenia. His birth was heralded by an angel telling his noble parents that he would abolish heresy and usher in an era of universal peace, which is why the called him Euthymius, “Good Cheer.” (We assume the angel was subsequently reassigned to a position that did not require delivery of prophecy.) After his father’s death, Euthymius was presented by his mother to the local bishop, who saw in the lad qualities the he did not see in himself, priested him under protest, and sent him off to look after the local monasteries and hermitages. Euthymius muttered into his swear jar and waited. When he was 29, he escaped and fled to Jerusalem. Escaping and fleeing got to be something of a theme for Euthymius, who was hounded by loyal fans from cave to cave, a phenomenon sometimes referred to as Euthymania†. With him went his loyal friend (St.) Theoctistus. Euthy (nobody called him Euthy) would later teach that it is bad for a monk to move about, and one should pick a place and dig in. Those of us who are parents know how he felt: “Kids, don’t make the same mistakes I made.”
His fame came in part from the many miraculous signs and wonders he performed. In addition to practicing medicine without a license, he also was known to drive out demons, multiply loaves (without an abacus), make barren women fruitful (by prayer, of course), and produce rain during times of drought. Would-be hermits should take note: if you really want to get away from the madding crowd and blend into the rockwork, flashy miracles are probably not the best way to go about it.
As you have already guessed, he and Theo eventually founded a lavra*. Theo became its hegumen*, or else Euthymius did. Our sources take great pains to tell us that this lavra was located on the right side of the road from Jerusalem to Jericho, so next time you’re in Palestine, if an unscrupulous tour guide tries to sell you a “Euthymius Slept Here” souvenir from a monastery on the left side of the road, don’t buy it.
Fabian, Pope of Rome (ca. 200–250), was a farmer on a tourist visa in Rome when the successor to Pope Anterus was being chosen. While he was waiting with everybody else for the holy decision, a dove flew down from heaven and landed on his head (which is better than some other things a dove can do on one’s head, I’m sure you’ll agree), causing the crowd to demand that he be made pope, which of course he was. Some say local dove retailers made a fortune over the next several years selling doves to ambitious clerics and training them to land on their heads, but Eusebius doesn’t mention this in his History of the Church, and he wasn’t the kind of guy to leave out a detail like that.
If the “more or less trustworthy” stories can be trusted, Fabian rebuilt the catacombs, fiddled with the numbers and types of holy orders, gerrymandered parish boundaries, had the relics of a previous pope exhumed in Sardinia and reburied in Rome, and sent seven deacons around the city collecting stories of the martyrs. He also sent seven bishops, each famous enough to warrant his own Wikipedia page, to Gaul as missionaries. He died a martyr under Decius, and was buried in the cemetery he himself had rebuilt. He is the patron of lead-founders and potters.
Sebastian (d. ca. 288 or 300), was a soldier so well thought of by Diocletian (that should send a shiver down your spine right there) that he made him leader of the Praetorian Guard. He immediately put himself in peril by using his high position to help imprisoned Christians. He also worked many miracles, made converts, set captives free, and in general did things that invited martyrdom. Diocletian heard of it and had him shot through with arrows and left for dead. He was nursed back to health, only to be beaten with cudgels and tossed, dead this time, into the sewers. One of the Station Churches (no room—look it up) was built on his grave, and he is one of the Fourteen Holy Helpers*. He is the patron saint of … archers.