In fact, Portia has nine suitors for her hand in marriage in Shakespeare's The Merchant of Venice.
In act 1, scene 2, Portia describes six of the suitors to Nerissa, Portia's "waiting woman."
NERISSA. But what warmth is there in
your affection towards any of these princely suitors that
are already come?
PORTIA. I pray thee, over-name them; and as thou namest
them I will describe them; and according to my description
level at my affection. (1.2.30-35)
These six suitors don't appear in the play, but Portia paints a very clear picture of each of them.
Portia describes the Neapolitan prince as a man who "doth nothing but talk of his horse" and that "he can shoe him himself" (1.2.37-38).
The Palatine count "doth nothing but frown...being so full of unmannerly sadness" (1.2.41- 45).
The French lord, Monsieur Le Bon? "God made him, and therefore let him pass for a man" (1.2.50).
As for Falconbridge, the English baron, Portia finds it impossible to converse with him in any of the languages that she knows. He also dresses poorly, in mismatched clothes from Italy, France, and Germany. (1.2.61-67)
The Scottish lord appears to lack courage, runs from a fight while threatening retaliation, and borrows money that he doesn't repay. (1.2.70-73)
Portia's opinion of the Duke of Saxony's nephew is that he behaves "Very vilely in the morning, when he is sober; and most vilely in the afternoon, when he is drunk" (1.2. 76-77). At his best, she says, "he is a little worse than a man," and at his worst "he is little better than a beast" (1.2.78-79).
Nerissa also mentions Bassanio, not as a suitor, but as a visitor to Portia's home when Portia's father was still alive.
NERISSA. Do you not remember, lady, in your father's time, a Venetian, a scholar and a soldier that came hither in
company of the Marquis of Montferrat?
PORTIA. Yes, yes, it was Bassanio; as I think, so was he
NERISSA. True, madam; he, of all the men that ever my foolish
eyes looked upon, was the best deserving a fair lady.
PORTIA. I remember him well; and I remember him worthy
of thy praise. (1.2.100-108)
The three suitors who actually appear in the play are The Prince of Morocco, the Prince of Arragon, and, finally, Bassanio—Portia's own choice for a husband.
The Prince of Morocco is flamboyant, overbearing, arrogant, incessantly boastful of himself in the most pompous and exaggerated terms, and he dresses all in white. Portia is pleased that he chooses the wrong casket, and she's understatedly happy to see him go.
PORTIA. A gentle riddance. (2.7.79)
The Prince of Arragon arrives—seemingly unannounced, if not altogether unexpectedly—to the sound of a flourish of cornets.
He doesn't stay long. He believes that the silver casket best represents his highly inflated sense of his self-worth.
ARRAGON. ...Who chooseth me, shall get as much as he deserves.
I will assume desert:—Give me a key for this,
And instantly unlock my fortunes here. (1.9.59-51)
The Prince of Arragon makes the wrong choice, and after reading the message in the casket, leaves Portia's home without another word.
Bassanio is the last of Portia's suitors, but the first in her heart. That Portia believes him to be a suitable husband, and that he's by far the most suitable of all her suitors, is all the character reference we need.
As a side note...towards the end of act 1, scene 2, one of Portia's servants seems to reference four more suitors.
MESSENGER. The four strangers seek for you, madam, to take their leave... (1.2.110-111)
Portia and Nerissa have been talking about six suitors, not four, and they haven't been talking about them as "strangers," even if they don't refer to them by name.
The "four strangers," if they're actually four additional suitors, apparently chose to remove themselves from contention as suitors for the same reason that the other six suitors did—they rejected the stringent terms that Portia's father imposed on anyone who wishes to choose from the three caskets in the hope of winning Portia as their wife.