Write a Program for winning sevens game
Synergistic

I'm not really a Python guy, but wanted to give this a go. This builds the set of playable cards at each turn, and assigns each of them a simple static score. The card with the highest score is played (assuming any playable card exists). 

def synergistic(cards_in_hand, played_cards):
    def list2dict(lst):
        d = {}
        for val, suit in lst:
            if suit in d:
                d[suit].append(val)
            else:
                d[suit] = [val]
        return d
    def play_card(card):
        cards_in_hand.remove(card)
        played_cards.append(card)

    hand = list2dict(cards_in_hand)
    if not played_cards:
        if 7 in hand['hearts']:
            play_card([7, 'hearts'])
        return (cards_in_hand, played_cards)
    table = list2dict(played_cards)

    playable_cards = {}
    for suit in hand:
        if 7 in hand[suit]:
            playable_cards[(7, suit)] = -1

        if suit not in table:
            continue
        visible = set(table[suit] + hand[suit])
        opp_hand = set(range(1,14)) - visible
        highcard = max(table[suit]) + 1

        if highcard in hand[suit]:
            if highcard+1 in opp_hand:
                playable_cards[(highcard, suit)] = 1
            else:
                playable_cards[(highcard, suit)] = 2

        lowcard = min(table[suit]) - 1
        if lowcard in hand[suit]:
            if lowcard - 1 in opp_hand:
                playable_cards[(lowcard, suit)] = 0
            else:
                playable_cards[(lowcard, suit)] = 1


    if not playable_cards:
        return (cards_in_hand, played_cards)

    best_card = list(max(playable_cards, key=playable_cards.get))
    #print(hand, "\n", table, "\n", best_card)
    play_card(best_card)

    return (cards_in_hand, played_cards)


By the way, the controller seemed to have several issues, including in score calculation and comparison. I made some changes to the controller here, please take a look  and update your version if this seems right.

Two things I haven't fixed in the controller: 


why is the loop condition (win2 &lt;= 50) and (win1 &lt;= 100) ? This should probably be symmetrical, it should exit the loop whenever either of the players has 100 consecutive wins. 
trying some runs of the controller locally, with the same function for both players, Player 2 seems to win most of the time - it can't be inherent to the game since the initial 7H requirement would smooth that out (as @Veskah mentioned in the comments), so, yet undetected controller bugs? Or my player code somehow maintaining state and having a bias this way? Per-game, it's not like Player 2 dominates heavily (from the results output txt), but somehow the overall score per controller run ends up favouring player 2 much more than random (Player 1's total scores are often more than 2x that of Player 2).