Tremendous
Tremendous, prodigious, extraordinary, exceptional, amazing, fantastic, overwhelming, unthinkable, unimaginable, unbelievable, unthought of, unutterable, ineffable, improbable, impossible, beyond one's wildest dreams, mind-boggling, amazeballs, stupendous, phenomenal, remarkable, astounding, astonishing, breathtaking, staggering, inconceivable, incredible, unheard of, unspeakable, untold, implausible, unlikely, undreamed of, beyond the realm of reason, and mind-blowing.
Excellent
Excellent, superb, first-rate, wonderful, exceptional, splendid, matchless, great, terrific, fantastic, stellar, fab, cool, magic, tip-top, out of sight, way-out, brill, on fleek, spiffing, top-hole, super-duper, marvellous, very good, first-class, outstanding, magnificent, superlative, peerless, super, tremendous, sensational, ace, A1, awesome, wicked, top-notch, out of this world, capital, smashing, bonzer, topping, and wizard.
Mythical
Mythical, mythic, fabled, fairy-tale, traditional, imaginary, made up, hypothetical, proverbial, allegorical, symbolical, legendary, mythological, folkloric, heroic, fictitious, imagined, unreal, fantastic, apocryphal, and symbolic.
Example Sentences of Fabulous
She wore a fabulous dress tonight.
He prepared a fabulous dinner yesterday.
The vacation was absolutely fabulous.
The performance was simply fabulous!